# Source code for inspect

    """Get useful information from live Python objects.

    This module encapsulates the interface provided by the internal special
    attributes (co_*, im_*, tb_*, etc.) in a friendlier fashion.
    It also provides some help for examining source code and class layout.

    Here are some of the useful functions provided by this module:

        ismodule(), isclass(), ismethod(), isfunction(), isgeneratorfunction(),
            isgenerator(), istraceback(), isframe(), iscode(), isbuiltin(),
            isroutine() - check object types
        getmembers() - get members of an object that satisfy a given condition

        getfile(), getsourcefile(), getsource() - find an object's source code
        getdoc(), getcomments() - get documentation on an object
        getmodule() - determine the module that an object came from
        getclasstree() - arrange classes so as to represent their hierarchy

        getargvalues(), getcallargs() - get info about function arguments
        getfullargspec() - same, with support for Python 3 features
        formatargvalues() - format an argument spec
        getouterframes(), getinnerframes() - get info about frames
        currentframe() - get the current stack frame
        stack(), trace() - get info about frames on the stack or in a traceback

        signature() - get a Signature object for the callable

        get_annotations() - safely compute an object's annotations
    """

    # This module is in the public domain.  No warranties.

    __author__ = ('Ka-Ping Yee <ping@lfw.org>',
                  'Yury Selivanov <yselivanov@sprymix.com>')

    import abc
    import ast
    import dis
    import collections.abc
    import enum
    import importlib.machinery
    import itertools
    import linecache
    import os
    import re
    import sys
    import tokenize
    import token
    import types
    import warnings
    import functools
    import builtins
    from operator import attrgetter
    from collections import namedtuple, OrderedDict

    # Create constants for the compiler flags in Include/code.h
    # We try to get them from dis to avoid duplication
    mod_dict = globals()
    for k, v in dis.COMPILER_FLAG_NAMES.items():
        mod_dict["CO_" + v] = k

    # See Include/object.h
    TPFLAGS_IS_ABSTRACT = 1 << 20

    def get_annotations(obj, *, globals=None, locals=None, eval_str=False):
        """Compute the annotations dict for an object.

        obj may be a callable, class, or module.
        Passing in an object of any other type raises TypeError.

        Returns a dict.  get_annotations() returns a new dict every time
        it's called; calling it twice on the same object will return two
        different but equivalent dicts.

        This function handles several details for you:

          * If eval_str is true, values of type str will
            be un-stringized using eval().  This is intended
            for use with stringized annotations
            ("from __future__ import annotations").
          * If obj doesn't have an annotations dict, returns an
            empty dict.  (Functions and methods always have an
            annotations dict; classes, modules, and other types of
            callables may not.)
          * Ignores inherited annotations on classes.  If a class
            doesn't have its own annotations dict, returns an empty dict.
          * All accesses to object members and dict values are done
            using getattr() and dict.get() for safety.
          * Always, always, always returns a freshly-created dict.

        eval_str controls whether or not values of type str are replaced
        with the result of calling eval() on those values:

          * If eval_str is true, eval() is called on values of type str.
          * If eval_str is false (the default), values of type str are unchanged.

        globals and locals are passed in to eval(); see the documentation
        for eval() for more information.  If either globals or locals is
        None, this function may replace that value with a context-specific
        default, contingent on type(obj):

          * If obj is a module, globals defaults to obj.__dict__.
          * If obj is a class, globals defaults to
            sys.modules[obj.__module__].__dict__ and locals
            defaults to the obj class namespace.
          * If obj is a callable, globals defaults to obj.__globals__,
            although if obj is a wrapped function (using
            functools.update_wrapper()) it is first unwrapped.
        """
        if isinstance(obj, type):
            # class
            obj_dict = getattr(obj, '__dict__', None)
            if obj_dict and hasattr(obj_dict, 'get'):
                ann = obj_dict.get('__annotations__', None)
                if isinstance(ann, types.GetSetDescriptorType):
                    ann = None
            else:
                ann = None

            obj_globals = None
            module_name = getattr(obj, '__module__', None)
            if module_name:
                module = sys.modules.get(module_name, None)
                if module:
                    obj_globals = getattr(module, '__dict__', None)
            obj_locals = dict(vars(obj))
            unwrap = obj
        elif isinstance(obj, types.ModuleType):
            # module
            ann = getattr(obj, '__annotations__', None)
            obj_globals = getattr(obj, '__dict__')
            obj_locals = None
            unwrap = None
        elif callable(obj):
            # this includes types.Function, types.BuiltinFunctionType,
            # types.BuiltinMethodType, functools.partial, functools.singledispatch,
            # "class funclike" from Lib/test/test_inspect... on and on it goes.
            ann = getattr(obj, '__annotations__', None)
            obj_globals = getattr(obj, '__globals__', None)
            obj_locals = None
            unwrap = obj
        else:
            raise TypeError(f"{obj!r} is not a module, class, or callable.")

        if ann is None:
            return {}

        if not isinstance(ann, dict):
            raise ValueError(f"{obj!r}.__annotations__ is neither a dict nor None")

        if not ann:
            return {}

        if not eval_str:
            return dict(ann)

        if unwrap is not None:
            while True:
                if hasattr(unwrap, '__wrapped__'):
                    unwrap = unwrap.__wrapped__
                    continue
                if isinstance(unwrap, functools.partial):
                    unwrap = unwrap.func
                    continue
                break
            if hasattr(unwrap, "__globals__"):
                obj_globals = unwrap.__globals__

        if globals is None:
            globals = obj_globals
        if locals is None:
            locals = obj_locals

        return_value = {key:
            value if not isinstance(value, str) else eval(value, globals, locals)
            for key, value in ann.items() }
        return return_value

    # ----------------------------------------------------------- type-checking
    def ismodule(object):
        """Return true if the object is a module.

        Module objects provide these attributes:
            __cached__      pathname to byte compiled file
            __doc__         documentation string
            __file__        filename (missing for built-in modules)"""
        return isinstance(object, types.ModuleType)

    def isclass(object):
        """Return true if the object is a class.

        Class objects provide these attributes:
            __doc__         documentation string
            __module__      name of module in which this class was defined"""
        return isinstance(object, type)

    def ismethod(object):
        """Return true if the object is an instance method.

        Instance method objects provide these attributes:
            __doc__         documentation string
            __name__        name with which this method was defined
            __func__        function object containing implementation of method
            __self__        instance to which this method is bound"""
        return isinstance(object, types.MethodType)

    def ismethoddescriptor(object):
        """Return true if the object is a method descriptor.

        But not if ismethod() or isclass() or isfunction() are true.

        This is new in Python 2.2, and, for example, is true of int.__add__.
        An object passing this test has a __get__ attribute but not a __set__
        attribute, but beyond that the set of attributes varies.  __name__ is
        usually sensible, and __doc__ often is.

        Methods implemented via descriptors that also pass one of the other
        tests return false from the ismethoddescriptor() test, simply because
        the other tests promise more -- you can, e.g., count on having the
        __func__ attribute (etc) when an object passes ismethod()."""
        if isclass(object) or ismethod(object) or isfunction(object):
            # mutual exclusion
            return False
        tp = type(object)
        return hasattr(tp, "__get__") and not hasattr(tp, "__set__")

    def isdatadescriptor(object):
        """Return true if the object is a data descriptor.

        Data descriptors have a __set__ or a __delete__ attribute.  Examples are
        properties (defined in Python) and getsets and members (defined in C).
        Typically, data descriptors will also have __name__ and __doc__ attributes
        (properties, getsets, and members have both of these attributes), but this
        is not guaranteed."""
        if isclass(object) or ismethod(object) or isfunction(object):
            # mutual exclusion
            return False
        tp = type(object)
        return hasattr(tp, "__set__") or hasattr(tp, "__delete__")

    if hasattr(types, 'MemberDescriptorType'):
        # CPython and equivalent
        def ismemberdescriptor(object):
            """Return true if the object is a member descriptor.

            Member descriptors are specialized descriptors defined in extension
            modules."""
            return isinstance(object, types.MemberDescriptorType)
    else:
        # Other implementations
        def ismemberdescriptor(object):
            """Return true if the object is a member descriptor.

            Member descriptors are specialized descriptors defined in extension
            modules."""
            return False

    if hasattr(types, 'GetSetDescriptorType'):
        # CPython and equivalent
        def isgetsetdescriptor(object):
            """Return true if the object is a getset descriptor.

            getset descriptors are specialized descriptors defined in extension
            modules."""
            return isinstance(object, types.GetSetDescriptorType)
    else:
        # Other implementations
        def isgetsetdescriptor(object):
            """Return true if the object is a getset descriptor.

            getset descriptors are specialized descriptors defined in extension
            modules."""
            return False

    def isfunction(object):
        """Return true if the object is a user-defined function.

        Function objects provide these attributes:
            __doc__         documentation string
            __name__        name with which this function was defined
            __code__        code object containing compiled function bytecode
            __defaults__    tuple of any default values for arguments
            __globals__     global namespace in which this function was defined
            __annotations__ dict of parameter annotations
            __kwdefaults__  dict of keyword only parameters with defaults"""
        return isinstance(object, types.FunctionType)

    def _has_code_flag(f, flag):
        """Return true if ``f`` is a function (or a method or functools.partial
        wrapper wrapping a function) whose code object has the given ``flag``
        set in its flags."""
        while ismethod(f):
            f = f.__func__
        f = functools._unwrap_partial(f)
        if not isfunction(f):
            return False
        return bool(f.__code__.co_flags & flag)

    def isgeneratorfunction(obj):
        """Return true if the object is a user-defined generator function.

        Generator function objects provide the same attributes as functions.
        See help(isfunction) for a list of attributes."""
        return _has_code_flag(obj, CO_GENERATOR)

    def iscoroutinefunction(obj):
        """Return true if the object is a coroutine function.

        Coroutine functions are defined with "async def" syntax.
        """
        return _has_code_flag(obj, CO_COROUTINE)

    def isasyncgenfunction(obj):
        """Return true if the object is an asynchronous generator function.

        Asynchronous generator functions are defined with "async def"
        syntax and have "yield" expressions in their body.
        """
        return _has_code_flag(obj, CO_ASYNC_GENERATOR)

    def isasyncgen(object):
        """Return true if the object is an asynchronous generator."""
        return isinstance(object, types.AsyncGeneratorType)

    def isgenerator(object):
        """Return true if the object is a generator.

        Generator objects provide these attributes:
            __iter__        defined to support iteration over container
            close           raises a new GeneratorExit exception inside the
                            generator to terminate the iteration
            gi_code         code object
            gi_frame        frame object or possibly None once the generator has
                            been exhausted
            gi_running      set to 1 when generator is executing, 0 otherwise
            next            return the next item from the container
            send            resumes the generator and "sends" a value that becomes
                            the result of the current yield-expression
            throw           used to raise an exception inside the generator"""
        return isinstance(object, types.GeneratorType)

    def iscoroutine(object):
        """Return true if the object is a coroutine."""
        return isinstance(object, types.CoroutineType)

    def isawaitable(object):
        """Return true if object can be passed to an ``await`` expression."""
        return (isinstance(object, types.CoroutineType) or
                isinstance(object, types.GeneratorType) and
                    bool(object.gi_code.co_flags & CO_ITERABLE_COROUTINE) or
                isinstance(object, collections.abc.Awaitable))

    def istraceback(object):
        """Return true if the object is a traceback.

        Traceback objects provide these attributes:
            tb_frame        frame object at this level
            tb_lasti        index of last attempted instruction in bytecode
            tb_lineno       current line number in Python source code
            tb_next         next inner traceback object (called by this level)"""
        return isinstance(object, types.TracebackType)

    def isframe(object):
        """Return true if the object is a frame object.

        Frame objects provide these attributes:
            f_back          next outer frame object (this frame's caller)
            f_builtins      built-in namespace seen by this frame
            f_code          code object being executed in this frame
            f_globals       global namespace seen by this frame
            f_lasti         index of last attempted instruction in bytecode
            f_lineno        current line number in Python source code
            f_locals        local namespace seen by this frame
            f_trace         tracing function for this frame, or None"""
        return isinstance(object, types.FrameType)

    def iscode(object):
        """Return true if the object is a code object.

        Code objects provide these attributes:
            co_argcount         number of arguments (not including *, ** args
                                or keyword only arguments)
            co_code             string of raw compiled bytecode
            co_cellvars         tuple of names of cell variables
            co_consts           tuple of constants used in the bytecode
            co_filename         name of file in which this code object was created
            co_firstlineno      number of first line in Python source code
            co_flags            bitmap: 1=optimized | 2=newlocals | 4=*arg | 8=**arg
                                | 16=nested | 32=generator | 64=nofree | 128=coroutine
                                | 256=iterable_coroutine | 512=async_generator
            co_freevars         tuple of names of free variables
            co_posonlyargcount  number of positional only arguments
            co_kwonlyargcount   number of keyword only arguments (not including ** arg)
            co_lnotab           encoded mapping of line numbers to bytecode indices
            co_name             name with which this code object was defined
            co_names            tuple of names other than arguments and function locals
            co_nlocals          number of local variables
            co_stacksize        virtual machine stack space required
            co_varnames         tuple of names of arguments and local variables"""
        return isinstance(object, types.CodeType)

    def isbuiltin(object):
        """Return true if the object is a built-in function or method.

        Built-in functions and methods provide these attributes:
            __doc__         documentation string
            __name__        original name of this function or method
            __self__        instance to which a method is bound, or None"""
        return isinstance(object, types.BuiltinFunctionType)

    def isroutine(object):
        """Return true if the object is any kind of function or method."""
        return (isbuiltin(object)
                or isfunction(object)
                or ismethod(object)
                or ismethoddescriptor(object))

    def isabstract(object):
        """Return true if the object is an abstract base class (ABC)."""
        if not isinstance(object, type):
            return False
        if object.__flags__ & TPFLAGS_IS_ABSTRACT:
            return True
        if not issubclass(type(object), abc.ABCMeta):
            return False
        if hasattr(object, '__abstractmethods__'):
            # It looks like ABCMeta.__new__ has finished running;
            # TPFLAGS_IS_ABSTRACT should have been accurate.
            return False
        # It looks like ABCMeta.__new__ has not finished running yet; we're
        # probably in __init_subclass__. We'll look for abstractmethods manually.
        for name, value in object.__dict__.items():
            if getattr(value, "__isabstractmethod__", False):
                return True
        for base in object.__bases__:
            for name in getattr(base, "__abstractmethods__", ()):
                value = getattr(object, name, None)
                if getattr(value, "__isabstractmethod__", False):
                    return True
        return False

    def getmembers(object, predicate=None):
        """Return all members of an object as (name, value) pairs sorted by name.
        Optionally, only return members that satisfy a given predicate."""
        if isclass(object):
            mro = (object,) + getmro(object)
        else:
            mro = ()
        results = []
        processed = set()
        names = dir(object)
        # :dd any DynamicClassAttributes to the list of names if object is a class;
        # this may result in duplicate entries if, for example, a virtual
        # attribute with the same name as a DynamicClassAttribute exists
        try:
            for base in object.__bases__:
                for k, v in base.__dict__.items():
                    if isinstance(v, types.DynamicClassAttribute):
                        names.append(k)
        except AttributeError:
            pass
        for key in names:
            # First try to get the value via getattr.  Some descriptors don't
            # like calling their __get__ (see bug #1785), so fall back to
            # looking in the __dict__.
            try:
                value = getattr(object, key)
                # handle the duplicate key
                if key in processed:
                    raise AttributeError
            except AttributeError:
                for base in mro:
                    if key in base.__dict__:
                        value = base.__dict__[key]
                        break
                else:
                    # could be a (currently) missing slot member, or a buggy
                    # __dir__; discard and move on
                    continue
            if not predicate or predicate(value):
                results.append((key, value))
            processed.add(key)
        results.sort(key=lambda pair: pair[0])
        return results

    Attribute = namedtuple('Attribute', 'name kind defining_class object')

    def classify_class_attrs(cls):
        """Return list of attribute-descriptor tuples.

        For each name in dir(cls), the return list contains a 4-tuple
        with these elements:

            0. The name (a string).

            1. The kind of attribute this is, one of these strings:
                   'class method'    created via classmethod()
                   'static method'   created via staticmethod()
                   'property'        created via property()
                   'method'          any other flavor of method or descriptor
                   'data'            not a method

            2. The class which defined this attribute (a class).

            3. The object as obtained by calling getattr; if this fails, or if the
               resulting object does not live anywhere in the class' mro (including
               metaclasses) then the object is looked up in the defining class's
               dict (found by walking the mro).

        If one of the items in dir(cls) is stored in the metaclass it will now
        be discovered and not have None be listed as the class in which it was
        defined.  Any items whose home class cannot be discovered are skipped.
        """

        mro = getmro(cls)
        metamro = getmro(type(cls)) # for attributes stored in the metaclass
        metamro = tuple(cls for cls in metamro if cls not in (type, object))
        class_bases = (cls,) + mro
        all_bases = class_bases + metamro
        names = dir(cls)
        # :dd any DynamicClassAttributes to the list of names;
        # this may result in duplicate entries if, for example, a virtual
        # attribute with the same name as a DynamicClassAttribute exists.
        for base in mro:
            for k, v in base.__dict__.items():
                if isinstance(v, types.DynamicClassAttribute) and v.fget is not None:
                    names.append(k)
        result = []
        processed = set()

        for name in names:
            # Get the object associated with the name, and where it was defined.
            # Normal objects will be looked up with both getattr and directly in
            # its class' dict (in case getattr fails [bug #1785], and also to look
            # for a docstring).
            # For DynamicClassAttributes on the second pass we only look in the
            # class's dict.
            #
            # Getting an obj from the __dict__ sometimes reveals more than
            # using getattr.  Static and class methods are dramatic examples.
            homecls = None
            get_obj = None
            dict_obj = None
            if name not in processed:
                try:
                    if name == '__dict__':
                        raise Exception("__dict__ is special, don't want the proxy")
                    get_obj = getattr(cls, name)
                except Exception as exc:
                    pass
                else:
                    homecls = getattr(get_obj, "__objclass__", homecls)
                    if homecls not in class_bases:
                        # if the resulting object does not live somewhere in the
                        # mro, drop it and search the mro manually
                        homecls = None
                        last_cls = None
                        # first look in the classes
                        for srch_cls in class_bases:
                            srch_obj = getattr(srch_cls, name, None)
                            if srch_obj is get_obj:
                                last_cls = srch_cls
                        # then check the metaclasses
                        for srch_cls in metamro:
                            try:
                                srch_obj = srch_cls.__getattr__(cls, name)
                            except AttributeError:
                                continue
                            if srch_obj is get_obj:
                                last_cls = srch_cls
                        if last_cls is not None:
                            homecls = last_cls
            for base in all_bases:
                if name in base.__dict__:
                    dict_obj = base.__dict__[name]
                    if homecls not in metamro:
                        homecls = base
                    break
            if homecls is None:
                # unable to locate the attribute anywhere, most likely due to
                # buggy custom __dir__; discard and move on
                continue
            obj = get_obj if get_obj is not None else dict_obj
            # Classify the object or its descriptor.
            if isinstance(dict_obj, (staticmethod, types.BuiltinMethodType)):
                kind = "static method"
                obj = dict_obj
            elif isinstance(dict_obj, (classmethod, types.ClassMethodDescriptorType)):
                kind = "class method"
                obj = dict_obj
            elif isinstance(dict_obj, property):
                kind = "property"
                obj = dict_obj
            elif isroutine(obj):
                kind = "method"
            else:
                kind = "data"
            result.append(Attribute(name, kind, homecls, obj))
            processed.add(name)
        return result

    # ----------------------------------------------------------- class helpers

    def getmro(cls):
        "Return tuple of base classes (including cls) in method resolution order."
        return cls.__mro__

    # -------------------------------------------------------- function helpers

    def unwrap(func, *, stop=None):
        """Get the object wrapped by *func*.

       Follows the chain of :attr:`__wrapped__` attributes returning the last
       object in the chain.

       *stop* is an optional callback accepting an object in the wrapper chain
       as its sole argument that allows the unwrapping to be terminated early if
       the callback returns a true value. If the callback never returns a true
       value, the last object in the chain is returned as usual. For example,
       :func:`signature` uses this to stop unwrapping if any object in the
       chain has a ``__signature__`` attribute defined.

       :exc:`ValueError` is raised if a cycle is encountered.

        """
        if stop is None:
            def _is_wrapper(f):
                return hasattr(f, '__wrapped__')
        else:
            def _is_wrapper(f):
                return hasattr(f, '__wrapped__') and not stop(f)
        f = func  # remember the original func for error reporting
        # Memoise by id to tolerate non-hashable objects, but store objects to
        # ensure they aren't destroyed, which would allow their IDs to be reused.
        memo = {id(f): f}
        recursion_limit = sys.getrecursionlimit()
        while _is_wrapper(func):
            func = func.__wrapped__
            id_func = id(func)
            if (id_func in memo) or (len(memo) >= recursion_limit):
                raise ValueError('wrapper loop when unwrapping {!r}'.format(f))
            memo[id_func] = func
        return func

    # -------------------------------------------------- source code extraction
    def indentsize(line):
        """Return the indent size, in spaces, at the start of a line of text."""
        expline = line.expandtabs()
        return len(expline) - len(expline.lstrip())

    def _findclass(func):
        cls = sys.modules.get(func.__module__)
        if cls is None:
            return None
        for name in func.__qualname__.split('.')[:-1]:
            cls = getattr(cls, name)
        if not isclass(cls):
            return None
        return cls

    def _finddoc(obj):
        if isclass(obj):
            for base in obj.__mro__:
                if base is not object:
                    try:
                        doc = base.__doc__
                    except AttributeError:
                        continue
                    if doc is not None:
                        return doc
            return None

        if ismethod(obj):
            name = obj.__func__.__name__
            self = obj.__self__
            if (isclass(self) and
                getattr(getattr(self, name, None), '__func__') is obj.__func__):
                # classmethod
                cls = self
            else:
                cls = self.__class__
        elif isfunction(obj):
            name = obj.__name__
            cls = _findclass(obj)
            if cls is None or getattr(cls, name) is not obj:
                return None
        elif isbuiltin(obj):
            name = obj.__name__
            self = obj.__self__
            if (isclass(self) and
                self.__qualname__ + '.' + name == obj.__qualname__):
                # classmethod
                cls = self
            else:
                cls = self.__class__
        # Should be tested before isdatadescriptor().
        elif isinstance(obj, property):
            func = obj.fget
            name = func.__name__
            cls = _findclass(func)
            if cls is None or getattr(cls, name) is not obj:
                return None
        elif ismethoddescriptor(obj) or isdatadescriptor(obj):
            name = obj.__name__
            cls = obj.__objclass__
            if getattr(cls, name) is not obj:
                return None
            if ismemberdescriptor(obj):
                slots = getattr(cls, '__slots__', None)
                if isinstance(slots, dict) and name in slots:
                    return slots[name]
        else:
            return None
        for base in cls.__mro__:
            try:
                doc = getattr(base, name).__doc__
            except AttributeError:
                continue
            if doc is not None:
                return doc
        return None

    def getdoc(object):
        """Get the documentation string for an object.

        All tabs are expanded to spaces.  To clean up docstrings that are
        indented to line up with blocks of code, any whitespace than can be
        uniformly removed from the second line onwards is removed."""
        try:
            doc = object.__doc__
        except AttributeError:
            return None
        if doc is None:
            try:
                doc = _finddoc(object)
            except (AttributeError, TypeError):
                return None
        if not isinstance(doc, str):
            return None
        return cleandoc(doc)

    def cleandoc(doc):
        """Clean up indentation from docstrings.

        Any whitespace that can be uniformly removed from the second line
        onwards is removed."""
        try:
            lines = doc.expandtabs().split('\n')
        except UnicodeError:
            return None
        else:
            # Find minimum indentation of any non-blank lines after first line.
            margin = sys.maxsize
            for line in lines[1:]:
                content = len(line.lstrip())
                if content:
                    indent = len(line) - content
                    margin = min(margin, indent)
            # Remove indentation.
            if lines:
                lines[0] = lines[0].lstrip()
            if margin < sys.maxsize:
                for i in range(1, len(lines)): lines[i] = lines[i][margin:]
            # Remove any trailing or leading blank lines.
            while lines and not lines[-1]:
                lines.pop()
            while lines and not lines[0]:
                lines.pop(0)
            return '\n'.join(lines)

    def getfile(object):
        """Work out which source or compiled file an object was defined in."""
        if ismodule(object):
            if getattr(object, '__file__', None):
                return object.__file__
            raise TypeError('{!r} is a built-in module'.format(object))
        if isclass(object):
            if hasattr(object, '__module__'):
                module = sys.modules.get(object.__module__)
                if getattr(module, '__file__', None):
                    return module.__file__
                if object.__module__ == '__main__':
                    raise OSError('source code not available')
            raise TypeError('{!r} is a built-in class'.format(object))
        if ismethod(object):
            object = object.__func__
        if isfunction(object):
            object = object.__code__
        if istraceback(object):
            object = object.tb_frame
        if isframe(object):
            object = object.f_code
        if iscode(object):
            return object.co_filename
        raise TypeError('module, class, method, function, traceback, frame, or '
                        'code object was expected, got {}'.format(
                        type(object).__name__))

    def getmodulename(path):
        """Return the module name for a given file, or None."""
        fname = os.path.basename(path)
        # Check for paths that look like an actual module file
        suffixes = [(-len(suffix), suffix)
                        for suffix in importlib.machinery.all_suffixes()]
        suffixes.sort() # try longest suffixes first, in case they overlap
        for neglen, suffix in suffixes:
            if fname.endswith(suffix):
                return fname[:neglen]
        return None

    def getsourcefile(object):
        """Return the filename that can be used to locate an object's source.
        Return None if no way can be identified to get the source.
        """
        filename = getfile(object)
        all_bytecode_suffixes = importlib.machinery.DEBUG_BYTECODE_SUFFIXES[:]
        all_bytecode_suffixes += importlib.machinery.OPTIMIZED_BYTECODE_SUFFIXES[:]
        if any(filename.endswith(s) for s in all_bytecode_suffixes):
            filename = (os.path.splitext(filename)[0] +
                        importlib.machinery.SOURCE_SUFFIXES[0])
        elif any(filename.endswith(s) for s in
                     importlib.machinery.EXTENSION_SUFFIXES):
            return None
        if os.path.exists(filename):
            return filename
        # only return a non-existent filename if the module has a PEP 302 loader
        module = getmodule(object, filename)
        if getattr(module, '__loader__', None) is not None:
            return filename
        elif getattr(getattr(module, "__spec__", None), "loader", None) is not None:
            return filename
        # or it is in the linecache
        elif filename in linecache.cache:
            return filename

    def getabsfile(object, _filename=None):
        """Return an absolute path to the source or compiled file for an object.

        The idea is for each object to have a unique origin, so this routine
        normalizes the result as much as possible."""
        if _filename is None:
            _filename = getsourcefile(object) or getfile(object)
        return os.path.normcase(os.path.abspath(_filename))

    modulesbyfile = {}
    _filesbymodname = {}

    def getmodule(object, _filename=None):
        """Return the module an object was defined in, or None if not found."""
        if ismodule(object):
            return object
        if hasattr(object, '__module__'):
            return sys.modules.get(object.__module__)
        # Try the filename to modulename cache
        if _filename is not None and _filename in modulesbyfile:
            return sys.modules.get(modulesbyfile[_filename])
        # Try the cache again with the absolute file name
        try:
            file = getabsfile(object, _filename)
        except (TypeError, FileNotFoundError):
            return None
        if file in modulesbyfile:
            return sys.modules.get(modulesbyfile[file])
        # Update the filename to module name cache and check yet again
        # Copy sys.modules in order to cope with changes while iterating
        for modname, module in sys.modules.copy().items():
            if ismodule(module) and hasattr(module, '__file__'):
                f = module.__file__
                if f == _filesbymodname.get(modname, None):
                    # Have already mapped this module, so skip it
                    continue
                _filesbymodname[modname] = f
                f = getabsfile(module)
                # Always map to the name the module knows itself by
                modulesbyfile[f] = modulesbyfile[
                    os.path.realpath(f)] = module.__name__
        if file in modulesbyfile:
            return sys.modules.get(modulesbyfile[file])
        # Check the main module
        main = sys.modules['__main__']
        if not hasattr(object, '__name__'):
            return None
        if hasattr(main, object.__name__):
            mainobject = getattr(main, object.__name__)
            if mainobject is object:
                return main
        # Check builtins
        builtin = sys.modules['builtins']
        if hasattr(builtin, object.__name__):
            builtinobject = getattr(builtin, object.__name__)
            if builtinobject is object:
                return builtin

    class ClassFoundException(Exception):
        pass

    class _ClassFinder(ast.NodeVisitor):

        def __init__(self, qualname):
            self.stack = []
            self.qualname = qualname

        def visit_FunctionDef(self, node):
            self.stack.append(node.name)
            self.stack.append('<locals>')
            self.generic_visit(node)
            self.stack.pop()
            self.stack.pop()

        visit_AsyncFunctionDef = visit_FunctionDef

        def visit_ClassDef(self, node):
            self.stack.append(node.name)
            if self.qualname == '.'.join(self.stack):
                # Return the decorator for the class if present
                if node.decorator_list:
                    line_number = node.decorator_list[0].lineno
                else:
                    line_number = node.lineno

                # decrement by one since lines starts with indexing by zero
                line_number -= 1
                raise ClassFoundException(line_number)
            self.generic_visit(node)
            self.stack.pop()

    def findsource(object):
        """Return the entire source file and starting line number for an object.

        The argument may be a module, class, method, function, traceback, frame,
        or code object.  The source code is returned as a list of all the lines
        in the file and the line number indexes a line in that list.  An OSError
        is raised if the source code cannot be retrieved."""

        file = getsourcefile(object)
        if file:
            # Invalidate cache if needed.
            linecache.checkcache(file)
        else:
            file = getfile(object)
            # Allow filenames in form of "<something>" to pass through.
            # `doctest` monkeypatches `linecache` module to enable
            # inspection, so let `linecache.getlines` to be called.
            if not (file.startswith('<') and file.endswith('>')):
                raise OSError('source code not available')

        module = getmodule(object, file)
        if module:
            lines = linecache.getlines(file, module.__dict__)
        else:
            lines = linecache.getlines(file)
        if not lines:
            raise OSError('could not get source code')

        if ismodule(object):
            return lines, 0

        if isclass(object):
            qualname = object.__qualname__
            source = ''.join(lines)
            tree = ast.parse(source)
            class_finder = _ClassFinder(qualname)
            try:
                class_finder.visit(tree)
            except ClassFoundException as e:
                line_number = e.args[0]
                return lines, line_number
            else:
                raise OSError('could not find class definition')

        if ismethod(object):
            object = object.__func__
        if isfunction(object):
            object = object.__code__
        if istraceback(object):
            object = object.tb_frame
        if isframe(object):
            object = object.f_code
        if iscode(object):
            if not hasattr(object, 'co_firstlineno'):
                raise OSError('could not find function definition')
            lnum = object.co_firstlineno - 1
            pat = re.compile(r'^(\s*def\s)|(\s*async\s+def\s)|(.*(?<!\w)lambda(:|\s))|^(\s*@)')
            while lnum > 0:
                try:
                    line = lines[lnum]
                except IndexError:
                    raise OSError('lineno is out of bounds')
                if pat.match(line):
                    break
                lnum = lnum - 1
            return lines, lnum
        raise OSError('could not find code object')

    def getcomments(object):
        """Get lines of comments immediately preceding an object's source code.

        Returns None when source can't be found.
        """
        try:
            lines, lnum = findsource(object)
        except (OSError, TypeError):
            return None

        if ismodule(object):
            # Look for a comment block at the top of the file.
            start = 0
            if lines and lines[0][:2] == '#!': start = 1
            while start < len(lines) and lines[start].strip() in ('', '#'):
                start = start + 1
            if start < len(lines) and lines[start][:1] == '#':
                comments = []
                end = start
                while end < len(lines) and lines[end][:1] == '#':
                    comments.append(lines[end].expandtabs())
                    end = end + 1
                return ''.join(comments)

        # Look for a preceding block of comments at the same indentation.
        elif lnum > 0:
            indent = indentsize(lines[lnum])
            end = lnum - 1
            if end >= 0 and lines[end].lstrip()[:1] == '#' and \
                indentsize(lines[end]) == indent:
                comments = [lines[end].expandtabs().lstrip()]
                if end > 0:
                    end = end - 1
                    comment = lines[end].expandtabs().lstrip()
                    while comment[:1] == '#' and indentsize(lines[end]) == indent:
                        comments[:0] = [comment]
                        end = end - 1
                        if end < 0: break
                        comment = lines[end].expandtabs().lstrip()
                while comments and comments[0].strip() == '#':
                    comments[:1] = []
                while comments and comments[-1].strip() == '#':
                    comments[-1:] = []
                return ''.join(comments)

    class EndOfBlock(Exception): pass

    class BlockFinder:
        """Provide a tokeneater() method to detect the end of a code block."""
        def __init__(self):
            self.indent = 0
            self.islambda = False
            self.started = False
            self.passline = False
            self.indecorator = False
            self.decoratorhasargs = False
            self.last = 1
            self.body_col0 = None

        def tokeneater(self, type, token, srowcol, erowcol, line):
            if not self.started and not self.indecorator:
                # skip any decorators
                if token == "@":
                    self.indecorator = True
                # look for the first "def", "class" or "lambda"
                elif token in ("def", "class", "lambda"):
                    if token == "lambda":
                        self.islambda = True
                    self.started = True
                self.passline = True    # skip to the end of the line
            elif token == "(":
                if self.indecorator:
                    self.decoratorhasargs = True
            elif token == ")":
                if self.indecorator:
                    self.indecorator = False
                    self.decoratorhasargs = False
            elif type == tokenize.NEWLINE:
                self.passline = False   # stop skipping when a NEWLINE is seen
                self.last = srowcol[0]
                if self.islambda:       # lambdas always end at the first NEWLINE
                    raise EndOfBlock
                # hitting a NEWLINE when in a decorator without args
                # ends the decorator
                if self.indecorator and not self.decoratorhasargs:
                    self.indecorator = False
            elif self.passline:
                pass
            elif type == tokenize.INDENT:
                if self.body_col0 is None and self.started:
                    self.body_col0 = erowcol[1]
                self.indent = self.indent + 1
                self.passline = True
            elif type == tokenize.DEDENT:
                self.indent = self.indent - 1
                # the end of matching indent/dedent pairs end a block
                # (note that this only works for "def"/"class" blocks,
                #  not e.g. for "if: else:" or "try: finally:" blocks)
                if self.indent <= 0:
                    raise EndOfBlock
            elif type == tokenize.COMMENT:
                if self.body_col0 is not None and srowcol[1] >= self.body_col0:
                    # Include comments if indented at least as much as the block
                    self.last = srowcol[0]
            elif self.indent == 0 and type not in (tokenize.COMMENT, tokenize.NL):
                # any other token on the same indentation level end the previous
                # block as well, except the pseudo-tokens COMMENT and NL.
                raise EndOfBlock

    def getblock(lines):
        """Extract the block of code at the top of the given list of lines."""
        blockfinder = BlockFinder()
        try:
            tokens = tokenize.generate_tokens(iter(lines).__next__)
            for _token in tokens:
                blockfinder.tokeneater(*_token)
        except (EndOfBlock, IndentationError):
            pass
        return lines[:blockfinder.last]

    def getsourcelines(object):
        """Return a list of source lines and starting line number for an object.

        The argument may be a module, class, method, function, traceback, frame,
        or code object.  The source code is returned as a list of the lines
        corresponding to the object and the line number indicates where in the
        original source file the first line of code was found.  An OSError is
        raised if the source code cannot be retrieved."""
        object = unwrap(object)
        lines, lnum = findsource(object)

        if istraceback(object):
            object = object.tb_frame

        # for module or frame that corresponds to module, return all source lines
        if (ismodule(object) or
            (isframe(object) and object.f_code.co_name == "<module>")):
            return lines, 0
        else:
            return getblock(lines[lnum:]), lnum + 1

    def getsource(object):
        """Return the text of the source code for an object.

        The argument may be a module, class, method, function, traceback, frame,
        or code object.  The source code is returned as a single string.  An
        OSError is raised if the source code cannot be retrieved."""
        lines, lnum = getsourcelines(object)
        return ''.join(lines)

    # --------------------------------------------------- class tree extraction
    def walktree(classes, children, parent):
        """Recursive helper function for getclasstree()."""
        results = []
        classes.sort(key=attrgetter('__module__', '__name__'))
        for c in classes:
            results.append((c, c.__bases__))
            if c in children:
                results.append(walktree(children[c], children, c))
        return results

    def getclasstree(classes, unique=False):
        """Arrange the given list of classes into a hierarchy of nested lists.

        Where a nested list appears, it contains classes derived from the class
        whose entry immediately precedes the list.  Each entry is a 2-tuple
        containing a class and a tuple of its base classes.  If the 'unique'
        argument is true, exactly one entry appears in the returned structure
        for each class in the given list.  Otherwise, classes using multiple
        inheritance and their descendants will appear multiple times."""
        children = {}
        roots = []
        for c in classes:
            if c.__bases__:
                for parent in c.__bases__:
                    if parent not in children:
                        children[parent] = []
                    if c not in children[parent]:
                        children[parent].append(c)
                    if unique and parent in classes: break
            elif c not in roots:
                roots.append(c)
        for parent in children:
            if parent not in classes:
                roots.append(parent)
        return walktree(roots, children, None)

    # ------------------------------------------------ argument list extraction
    Arguments = namedtuple('Arguments', 'args, varargs, varkw')

    def getargs(co):
        """Get information about the arguments accepted by a code object.

        Three things are returned: (args, varargs, varkw), where
        'args' is the list of argument names. Keyword-only arguments are
        appended. 'varargs' and 'varkw' are the names of the * and **
        arguments or None."""
        if not iscode(co):
            raise TypeError('{!r} is not a code object'.format(co))

        names = co.co_varnames
        nargs = co.co_argcount
        nkwargs = co.co_kwonlyargcount
        args = list(names[:nargs])
        kwonlyargs = list(names[nargs:nargs+nkwargs])
        step = 0

        nargs += nkwargs
        varargs = None
        if co.co_flags & CO_VARARGS:
            varargs = co.co_varnames[nargs]
            nargs = nargs + 1
        varkw = None
        if co.co_flags & CO_VARKEYWORDS:
            varkw = co.co_varnames[nargs]
        return Arguments(args + kwonlyargs, varargs, varkw)

    ArgSpec = namedtuple('ArgSpec', 'args varargs keywords defaults')

    def getargspec(func):
        """Get the names and default values of a function's parameters.

        A tuple of four things is returned: (args, varargs, keywords, defaults).
        'args' is a list of the argument names, including keyword-only argument names.
        'varargs' and 'keywords' are the names of the * and ** parameters or None.
        'defaults' is an n-tuple of the default values of the last n parameters.

        This function is deprecated, as it does not support annotations or
        keyword-only parameters and will raise ValueError if either is present
        on the supplied callable.

        For a more structured introspection API, use inspect.signature() instead.

        Alternatively, use getfullargspec() for an API with a similar namedtuple
        based interface, but full support for annotations and keyword-only
        parameters.

        Deprecated since Python 3.5, use `inspect.getfullargspec()`.
        """
        warnings.warn("inspect.getargspec() is deprecated since Python 3.0, "
                      "use inspect.signature() or inspect.getfullargspec()",
                      DeprecationWarning, stacklevel=2)
        args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, ann = \
            getfullargspec(func)
        if kwonlyargs or ann:
            raise ValueError("Function has keyword-only parameters or annotations"
                             ", use inspect.signature() API which can support them")
        return ArgSpec(args, varargs, varkw, defaults)

    FullArgSpec = namedtuple('FullArgSpec',
        'args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, annotations')

    def getfullargspec(func):
        """Get the names and default values of a callable object's parameters.

        A tuple of seven things is returned:
        (args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, annotations).
        'args' is a list of the parameter names.
        'varargs' and 'varkw' are the names of the * and ** parameters or None.
        'defaults' is an n-tuple of the default values of the last n parameters.
        'kwonlyargs' is a list of keyword-only parameter names.
        'kwonlydefaults' is a dictionary mapping names from kwonlyargs to defaults.
        'annotations' is a dictionary mapping parameter names to annotations.

        Notable differences from inspect.signature():
          - the "self" parameter is always reported, even for bound methods
          - wrapper chains defined by __wrapped__ *not* unwrapped automatically
        """
        try:
            # Re: `skip_bound_arg=False`
            #
            # There is a notable difference in behaviour between getfullargspec
            # and Signature: the former always returns 'self' parameter for bound
            # methods, whereas the Signature always shows the actual calling
            # signature of the passed object.
            #
            # To simulate this behaviour, we "unbind" bound methods, to trick
            # inspect.signature to always return their first parameter ("self",
            # usually)

            # Re: `follow_wrapper_chains=False`
            #
            # getfullargspec() historically ignored __wrapped__ attributes,
            # so we ensure that remains the case in 3.3+

            sig = _signature_from_callable(func,
                                           follow_wrapper_chains=False,
                                           skip_bound_arg=False,
                                           sigcls=Signature,
                                           eval_str=False)
        except Exception as ex:
            # Most of the times 'signature' will raise ValueError.
            # But, it can also raise AttributeError, and, maybe something
            # else. So to be fully backwards compatible, we catch all
            # possible exceptions here, and reraise a TypeError.
            raise TypeError('unsupported callable') from ex

        args = []
        varargs = None
        varkw = None
        posonlyargs = []
        kwonlyargs = []
        annotations = {}
        defaults = ()
        kwdefaults = {}

        if sig.return_annotation is not sig.empty:
            annotations['return'] = sig.return_annotation

        for param in sig.parameters.values():
            kind = param.kind
            name = param.name

            if kind is _POSITIONAL_ONLY:
                posonlyargs.append(name)
                if param.default is not param.empty:
                    defaults += (param.default,)
            elif kind is _POSITIONAL_OR_KEYWORD:
                args.append(name)
                if param.default is not param.empty:
                    defaults += (param.default,)
            elif kind is _VAR_POSITIONAL:
                varargs = name
            elif kind is _KEYWORD_ONLY:
                kwonlyargs.append(name)
                if param.default is not param.empty:
                    kwdefaults[name] = param.default
            elif kind is _VAR_KEYWORD:
                varkw = name

            if param.annotation is not param.empty:
                annotations[name] = param.annotation

        if not kwdefaults:
            # compatibility with 'func.__kwdefaults__'
            kwdefaults = None

        if not defaults:
            # compatibility with 'func.__defaults__'
            defaults = None

        return FullArgSpec(posonlyargs + args, varargs, varkw, defaults,
                           kwonlyargs, kwdefaults, annotations)

    ArgInfo = namedtuple('ArgInfo', 'args varargs keywords locals')

    def getargvalues(frame):
        """Get information about arguments passed into a particular frame.

        A tuple of four things is returned: (args, varargs, varkw, locals).
        'args' is a list of the argument names.
        'varargs' and 'varkw' are the names of the * and ** arguments or None.
        'locals' is the locals dictionary of the given frame."""
        args, varargs, varkw = getargs(frame.f_code)
        return ArgInfo(args, varargs, varkw, frame.f_locals)

    def formatannotation(annotation, base_module=None):
        if getattr(annotation, '__module__', None) == 'typing':
            return repr(annotation).replace('typing.', '')
        if isinstance(annotation, types.GenericAlias):
            return str(annotation)
        if isinstance(annotation, type):
            if annotation.__module__ in ('builtins', base_module):
                return annotation.__qualname__
            return annotation.__module__+'.'+annotation.__qualname__
        return repr(annotation)

    def formatannotationrelativeto(object):
        module = getattr(object, '__module__', None)
        def _formatannotation(annotation):
            return formatannotation(annotation, module)
        return _formatannotation

    def formatargspec(args, varargs=None, varkw=None, defaults=None,
                      kwonlyargs=(), kwonlydefaults={}, annotations={},
                      formatarg=str,
                      formatvarargs=lambda name: '*' + name,
                      formatvarkw=lambda name: '**' + name,
                      formatvalue=lambda value: '=' + repr(value),
                      formatreturns=lambda text: ' -> ' + text,
                      formatannotation=formatannotation):
        """Format an argument spec from the values returned by getfullargspec.

        The first seven arguments are (args, varargs, varkw, defaults,
        kwonlyargs, kwonlydefaults, annotations).  The other five arguments
        are the corresponding optional formatting functions that are called to
        turn names and values into strings.  The last argument is an optional
        function to format the sequence of arguments.

        Deprecated since Python 3.5: use the `signature` function and `Signature`
        objects.
        """

        from warnings import warn

        warn("`formatargspec` is deprecated since Python 3.5. Use `signature` and "
             "the `Signature` object directly",
             DeprecationWarning,
             stacklevel=2)

        def formatargandannotation(arg):
            result = formatarg(arg)
            if arg in annotations:
                result += ': ' + formatannotation(annotations[arg])
            return result
        specs = []
        if defaults:
            firstdefault = len(args) - len(defaults)
        for i, arg in enumerate(args):
            spec = formatargandannotation(arg)
            if defaults and i >= firstdefault:
                spec = spec + formatvalue(defaults[i - firstdefault])
            specs.append(spec)
        if varargs is not None:
            specs.append(formatvarargs(formatargandannotation(varargs)))
        else:
            if kwonlyargs:
                specs.append('*')
        if kwonlyargs:
            for kwonlyarg in kwonlyargs:
                spec = formatargandannotation(kwonlyarg)
                if kwonlydefaults and kwonlyarg in kwonlydefaults:
                    spec += formatvalue(kwonlydefaults[kwonlyarg])
                specs.append(spec)
        if varkw is not None:
            specs.append(formatvarkw(formatargandannotation(varkw)))
        result = '(' + ', '.join(specs) + ')'
        if 'return' in annotations:
            result += formatreturns(formatannotation(annotations['return']))
        return result

    def formatargvalues(args, varargs, varkw, locals,
                        formatarg=str,
                        formatvarargs=lambda name: '*' + name,
                        formatvarkw=lambda name: '**' + name,
                        formatvalue=lambda value: '=' + repr(value)):
        """Format an argument spec from the 4 values returned by getargvalues.

        The first four arguments are (args, varargs, varkw, locals).  The
        next four arguments are the corresponding optional formatting functions
        that are called to turn names and values into strings.  The ninth
        argument is an optional function to format the sequence of arguments."""
        def convert(name, locals=locals,
                    formatarg=formatarg, formatvalue=formatvalue):
            return formatarg(name) + formatvalue(locals[name])
        specs = []
        for i in range(len(args)):
            specs.append(convert(args[i]))
        if varargs:
            specs.append(formatvarargs(varargs) + formatvalue(locals[varargs]))
        if varkw:
            specs.append(formatvarkw(varkw) + formatvalue(locals[varkw]))
        return '(' + ', '.join(specs) + ')'

    def _missing_arguments(f_name, argnames, pos, values):
        names = [repr(name) for name in argnames if name not in values]
        missing = len(names)
        if missing == 1:
            s = names[0]
        elif missing == 2:
            s = "{} and {}".format(*names)
        else:
            tail = ", {} and {}".format(*names[-2:])
            del names[-2:]
            s = ", ".join(names) + tail
        raise TypeError("%s() missing %i required %s argument%s: %s" %
                        (f_name, missing,
                          "positional" if pos else "keyword-only",
                          "" if missing == 1 else "s", s))

    def _too_many(f_name, args, kwonly, varargs, defcount, given, values):
        atleast = len(args) - defcount
        kwonly_given = len([arg for arg in kwonly if arg in values])
        if varargs:
            plural = atleast != 1
            sig = "at least %d" % (atleast,)
        elif defcount:
            plural = True
            sig = "from %d to %d" % (atleast, len(args))
        else:
            plural = len(args) != 1
            sig = str(len(args))
        kwonly_sig = ""
        if kwonly_given:
            msg = " positional argument%s (and %d keyword-only argument%s)"
            kwonly_sig = (msg % ("s" if given != 1 else "", kwonly_given,
                                 "s" if kwonly_given != 1 else ""))
        raise TypeError("%s() takes %s positional argument%s but %d%s %s given" %
                (f_name, sig, "s" if plural else "", given, kwonly_sig,
                 "was" if given == 1 and not kwonly_given else "were"))

    def getcallargs(func, /, *positional, **named):
        """Get the mapping of arguments to values.

        A dict is returned, with keys the function argument names (including the
        names of the * and ** arguments, if any), and values the respective bound
        values from 'positional' and 'named'."""
        spec = getfullargspec(func)
        args, varargs, varkw, defaults, kwonlyargs, kwonlydefaults, ann = spec
        f_name = func.__name__
        arg2value = {}

        if ismethod(func) and func.__self__ is not None:
            # implicit 'self' (or 'cls' for classmethods) argument
            positional = (func.__self__,) + positional
        num_pos = len(positional)
        num_args = len(args)
        num_defaults = len(defaults) if defaults else 0

        n = min(num_pos, num_args)
        for i in range(n):
            arg2value[args[i]] = positional[i]
        if varargs:
            arg2value[varargs] = tuple(positional[n:])
        possible_kwargs = set(args + kwonlyargs)
        if varkw:
            arg2value[varkw] = {}
        for kw, value in named.items():
            if kw not in possible_kwargs:
                if not varkw:
                    raise TypeError("%s() got an unexpected keyword argument %r" %
                                    (f_name, kw))
                arg2value[varkw][kw] = value
                continue
            if kw in arg2value:
                raise TypeError("%s() got multiple values for argument %r" %
                                (f_name, kw))
            arg2value[kw] = value
        if num_pos > num_args and not varargs:
            _too_many(f_name, args, kwonlyargs, varargs, num_defaults,
                       num_pos, arg2value)
        if num_pos < num_args:
            req = args[:num_args - num_defaults]
            for arg in req:
                if arg not in arg2value:
                    _missing_arguments(f_name, req, True, arg2value)
            for i, arg in enumerate(args[num_args - num_defaults:]):
                if arg not in arg2value:
                    arg2value[arg] = defaults[i]
        missing = 0
        for kwarg in kwonlyargs:
            if kwarg not in arg2value:
                if kwonlydefaults and kwarg in kwonlydefaults:
                    arg2value[kwarg] = kwonlydefaults[kwarg]
                else:
                    missing += 1
        if missing:
            _missing_arguments(f_name, kwonlyargs, False, arg2value)
        return arg2value

    ClosureVars = namedtuple('ClosureVars', 'nonlocals globals builtins unbound')

    def getclosurevars(func):
        """
        Get the mapping of free variables to their current values.

        Returns a named tuple of dicts mapping the current nonlocal, global
        and builtin references as seen by the body of the function. A final
        set of unbound names that could not be resolved is also provided.
        """

        if ismethod(func):
            func = func.__func__

        if not isfunction(func):
            raise TypeError("{!r} is not a Python function".format(func))

        code = func.__code__
        # Nonlocal references are named in co_freevars and resolved
        # by looking them up in __closure__ by positional index
        if func.__closure__ is None:
            nonlocal_vars = {}
        else:
            nonlocal_vars = {
                var : cell.cell_contents
                for var, cell in zip(code.co_freevars, func.__closure__)
           }

        # Global and builtin references are named in co_names and resolved
        # by looking them up in __globals__ or __builtins__
        global_ns = func.__globals__
        builtin_ns = global_ns.get("__builtins__", builtins.__dict__)
        if ismodule(builtin_ns):
            builtin_ns = builtin_ns.__dict__
        global_vars = {}
        builtin_vars = {}
        unbound_names = set()
        for name in code.co_names:
            if name in ("None", "True", "False"):
                # Because these used to be builtins instead of keywords, they
                # may still show up as name references. We ignore them.
                continue
            try:
                global_vars[name] = global_ns[name]
            except KeyError:
                try:
                    builtin_vars[name] = builtin_ns[name]
                except KeyError:
                    unbound_names.add(name)

        return ClosureVars(nonlocal_vars, global_vars,
                           builtin_vars, unbound_names)

    # -------------------------------------------------- stack frame extraction

    Traceback = namedtuple('Traceback', 'filename lineno function code_context index')

    def getframeinfo(frame, context=1):
        """Get information about a frame or traceback object.

        A tuple of five things is returned: the filename, the line number of
        the current line, the function name, a list of lines of context from
        the source code, and the index of the current line within that list.
        The optional second argument specifies the number of lines of context
        to return, which are centered around the current line."""
        if istraceback(frame):
            lineno = frame.tb_lineno
            frame = frame.tb_frame
        else:
            lineno = frame.f_lineno
        if not isframe(frame):
            raise TypeError('{!r} is not a frame or traceback object'.format(frame))

        filename = getsourcefile(frame) or getfile(frame)
        if context > 0:
            start = lineno - 1 - context//2
            try:
                lines, lnum = findsource(frame)
            except OSError:
                lines = index = None
            else:
                start = max(0, min(start, len(lines) - context))
                lines = lines[start:start+context]
                index = lineno - 1 - start
        else:
            lines = index = None

        return Traceback(filename, lineno, frame.f_code.co_name, lines, index)

    def getlineno(frame):
        """Get the line number from a frame object, allowing for optimization."""
        # FrameType.f_lineno is now a descriptor that grovels co_lnotab
        return frame.f_lineno

    FrameInfo = namedtuple('FrameInfo', ('frame',) + Traceback._fields)

    def getouterframes(frame, context=1):
        """Get a list of records for a frame and all higher (calling) frames.

        Each record contains a frame object, filename, line number, function
        name, a list of lines of context, and index within the context."""
        framelist = []
        while frame:
            frameinfo = (frame,) + getframeinfo(frame, context)
            framelist.append(FrameInfo(*frameinfo))
            frame = frame.f_back
        return framelist

    def getinnerframes(tb, context=1):
        """Get a list of records for a traceback's frame and all lower frames.

        Each record contains a frame object, filename, line number, function
        name, a list of lines of context, and index within the context."""
        framelist = []
        while tb:
            frameinfo = (tb.tb_frame,) + getframeinfo(tb, context)
            framelist.append(FrameInfo(*frameinfo))
            tb = tb.tb_next
        return framelist

    def currentframe():
        """Return the frame of the caller or None if this is not possible."""
        return sys._getframe(1) if hasattr(sys, "_getframe") else None

    def stack(context=1):
        """Return a list of records for the stack above the caller's frame."""
        return getouterframes(sys._getframe(1), context)

    def trace(context=1):
        """Return a list of records for the stack below the current exception."""
        return getinnerframes(sys.exc_info()[2], context)

    # ------------------------------------------------ static version of getattr

    _sentinel = object()

    def _static_getmro(klass):
        return type.__dict__['__mro__'].__get__(klass)

    def _check_instance(obj, attr):
        instance_dict = {}
        try:
            instance_dict = object.__getattribute__(obj, "__dict__")
        except AttributeError:
            pass
        return dict.get(instance_dict, attr, _sentinel)

    def _check_class(klass, attr):
        for entry in _static_getmro(klass):
            if _shadowed_dict(type(entry)) is _sentinel:
                try:
                    return entry.__dict__[attr]
                except KeyError:
                    pass
        return _sentinel

    def _is_type(obj):
        try:
            _static_getmro(obj)
        except TypeError:
            return False
        return True

    def _shadowed_dict(klass):
        dict_attr = type.__dict__["__dict__"]
        for entry in _static_getmro(klass):
            try:
                class_dict = dict_attr.__get__(entry)["__dict__"]
            except KeyError:
                pass
            else:
                if not (type(class_dict) is types.GetSetDescriptorType and
                        class_dict.__name__ == "__dict__" and
                        class_dict.__objclass__ is entry):
                    return class_dict
        return _sentinel

    def getattr_static(obj, attr, default=_sentinel):
        """Retrieve attributes without triggering dynamic lookup via the
           descriptor protocol,  __getattr__ or __getattribute__.

           Note: this function may not be able to retrieve all attributes
           that getattr can fetch (like dynamically created attributes)
           and may find attributes that getattr can't (like descriptors
           that raise AttributeError). It can also return descriptor objects
           instead of instance members in some cases. See the
           documentation for details.
        """
        instance_result = _sentinel
        if not _is_type(obj):
            klass = type(obj)
            dict_attr = _shadowed_dict(klass)
            if (dict_attr is _sentinel or
                type(dict_attr) is types.MemberDescriptorType):
                instance_result = _check_instance(obj, attr)
        else:
            klass = obj

        klass_result = _check_class(klass, attr)

        if instance_result is not _sentinel and klass_result is not _sentinel:
            if (_check_class(type(klass_result), '__get__') is not _sentinel and
                _check_class(type(klass_result), '__set__') is not _sentinel):
                return klass_result

        if instance_result is not _sentinel:
            return instance_result
        if klass_result is not _sentinel:
            return klass_result

        if obj is klass:
            # for types we check the metaclass too
            for entry in _static_getmro(type(klass)):
                if _shadowed_dict(type(entry)) is _sentinel:
                    try:
                        return entry.__dict__[attr]
                    except KeyError:
                        pass
        if default is not _sentinel:
            return default
        raise AttributeError(attr)

    # ------------------------------------------------ generator introspection

    GEN_CREATED = 'GEN_CREATED'
    GEN_RUNNING = 'GEN_RUNNING'
    GEN_SUSPENDED = 'GEN_SUSPENDED'
    GEN_CLOSED = 'GEN_CLOSED'

    def getgeneratorstate(generator):
        """Get current state of a generator-iterator.

        Possible states are:
          GEN_CREATED: Waiting to start execution.
          GEN_RUNNING: Currently being executed by the interpreter.
          GEN_SUSPENDED: Currently suspended at a yield expression.
          GEN_CLOSED: Execution has completed.
        """
        if generator.gi_running:
            return GEN_RUNNING
        if generator.gi_frame is None:
            return GEN_CLOSED
        if generator.gi_frame.f_lasti == -1:
            return GEN_CREATED
        return GEN_SUSPENDED

    def getgeneratorlocals(generator):
        """
        Get the mapping of generator local variables to their current values.

        A dict is returned, with the keys the local variable names and values the
        bound values."""

        if not isgenerator(generator):
            raise TypeError("{!r} is not a Python generator".format(generator))

        frame = getattr(generator, "gi_frame", None)
        if frame is not None:
            return generator.gi_frame.f_locals
        else:
            return {}

    # ------------------------------------------------ coroutine introspection

    CORO_CREATED = 'CORO_CREATED'
    CORO_RUNNING = 'CORO_RUNNING'
    CORO_SUSPENDED = 'CORO_SUSPENDED'
    CORO_CLOSED = 'CORO_CLOSED'

    def getcoroutinestate(coroutine):
        """Get current state of a coroutine object.

        Possible states are:
          CORO_CREATED: Waiting to start execution.
          CORO_RUNNING: Currently being executed by the interpreter.
          CORO_SUSPENDED: Currently suspended at an await expression.
          CORO_CLOSED: Execution has completed.
        """
        if coroutine.cr_running:
            return CORO_RUNNING
        if coroutine.cr_frame is None:
            return CORO_CLOSED
        if coroutine.cr_frame.f_lasti == -1:
            return CORO_CREATED
        return CORO_SUSPENDED

    def getcoroutinelocals(coroutine):
        """
        Get the mapping of coroutine local variables to their current values.

        A dict is returned, with the keys the local variable names and values the
        bound values."""
        frame = getattr(coroutine, "cr_frame", None)
        if frame is not None:
            return frame.f_locals
        else:
            return {}

    ###############################################################################
    ### Function Signature Object (PEP 362)
    ###############################################################################

    _WrapperDescriptor = type(type.__call__)
    _MethodWrapper = type(all.__call__)
    _ClassMethodWrapper = type(int.__dict__['from_bytes'])

    _NonUserDefinedCallables = (_WrapperDescriptor,
                                _MethodWrapper,
                                _ClassMethodWrapper,
                                types.BuiltinFunctionType)

    def _signature_get_user_defined_method(cls, method_name):
        """Private helper. Checks if ``cls`` has an attribute
        named ``method_name`` and returns it only if it is a
        pure python function.
        """
        try:
            meth = getattr(cls, method_name)
        except AttributeError:
            return
        else:
            if not isinstance(meth, _NonUserDefinedCallables):
                # Once '__signature__' will be added to 'C'-level
                # callables, this check won't be necessary
                return meth

    def _signature_get_partial(wrapped_sig, partial, extra_args=()):
        """Private helper to calculate how 'wrapped_sig' signature will
        look like after applying a 'functools.partial' object (or alike)
        on it.
        """

        old_params = wrapped_sig.parameters
        new_params = OrderedDict(old_params.items())

        partial_args = partial.args or ()
        partial_keywords = partial.keywords or {}

        if extra_args:
            partial_args = extra_args + partial_args

        try:
            ba = wrapped_sig.bind_partial(*partial_args, **partial_keywords)
        except TypeError as ex:
            msg = 'partial object {!r} has incorrect arguments'.format(partial)
            raise ValueError(msg) from ex

        transform_to_kwonly = False
        for param_name, param in old_params.items():
            try:
                arg_value = ba.arguments[param_name]
            except KeyError:
                pass
            else:
                if param.kind is _POSITIONAL_ONLY:
                    # If positional-only parameter is bound by partial,
                    # it effectively disappears from the signature
                    new_params.pop(param_name)
                    continue

                if param.kind is _POSITIONAL_OR_KEYWORD:
                    if param_name in partial_keywords:
                        # This means that this parameter, and all parameters
                        # after it should be keyword-only (and var-positional
                        # should be removed). Here's why. Consider the following
                        # function:
                        #     foo(a, b, *args, c):
                        #         pass
                        #
                        # "partial(foo, a='spam')" will have the following
                        # signature: "(*, a='spam', b, c)". Because attempting
                        # to call that partial with "(10, 20)" arguments will
                        # raise a TypeError, saying that "a" argument received
                        # multiple values.
                        transform_to_kwonly = True
                        # Set the new default value
                        new_params[param_name] = param.replace(default=arg_value)
                    else:
                        # was passed as a positional argument
                        new_params.pop(param.name)
                        continue

                if param.kind is _KEYWORD_ONLY:
                    # Set the new default value
                    new_params[param_name] = param.replace(default=arg_value)

            if transform_to_kwonly:
                assert param.kind is not _POSITIONAL_ONLY

                if param.kind is _POSITIONAL_OR_KEYWORD:
                    new_param = new_params[param_name].replace(kind=_KEYWORD_ONLY)
                    new_params[param_name] = new_param
                    new_params.move_to_end(param_name)
                elif param.kind in (_KEYWORD_ONLY, _VAR_KEYWORD):
                    new_params.move_to_end(param_name)
                elif param.kind is _VAR_POSITIONAL:
                    new_params.pop(param.name)

        return wrapped_sig.replace(parameters=new_params.values())

    def _signature_bound_method(sig):
        """Private helper to transform signatures for unbound
        functions to bound methods.
        """

        params = tuple(sig.parameters.values())

        if not params or params[0].kind in (_VAR_KEYWORD, _KEYWORD_ONLY):
            raise ValueError('invalid method signature')

        kind = params[0].kind
        if kind in (_POSITIONAL_OR_KEYWORD, _POSITIONAL_ONLY):
            # Drop first parameter:
            # '(p1, p2[, ...])' -> '(p2[, ...])'
            params = params[1:]
        else:
            if kind is not _VAR_POSITIONAL:
                # Unless we add a new parameter type we never
                # get here
                raise ValueError('invalid argument type')
            # It's a var-positional parameter.
            # Do nothing. '(*args[, ...])' -> '(*args[, ...])'

        return sig.replace(parameters=params)

    def _signature_is_builtin(obj):
        """Private helper to test if `obj` is a callable that might
        support Argument Clinic's __text_signature__ protocol.
        """
        return (isbuiltin(obj) or
                ismethoddescriptor(obj) or
                isinstance(obj, _NonUserDefinedCallables) or
                # Can't test 'isinstance(type)' here, as it would
                # also be True for regular python classes
                obj in (type, object))

    def _signature_is_functionlike(obj):
        """Private helper to test if `obj` is a duck type of FunctionType.
        A good example of such objects are functions compiled with
        Cython, which have all attributes that a pure Python function
        would have, but have their code statically compiled.
        """

        if not callable(obj) or isclass(obj):
            # All function-like objects are obviously callables,
            # and not classes.
            return False

        name = getattr(obj, '__name__', None)
        code = getattr(obj, '__code__', None)
        defaults = getattr(obj, '__defaults__', _void) # Important to use _void ...
        kwdefaults = getattr(obj, '__kwdefaults__', _void) # ... and not None here
        annotations = getattr(obj, '__annotations__', None)

        return (isinstance(code, types.CodeType) and
                isinstance(name, str) and
                (defaults is None or isinstance(defaults, tuple)) and
                (kwdefaults is None or isinstance(kwdefaults, dict)) and
                (isinstance(annotations, (dict)) or annotations is None) )

    def _signature_get_bound_param(spec):
        """ Private helper to get first parameter name from a
        __text_signature__ of a builtin method, which should
        be in the following format: '($param1, ...)'.
        Assumptions are that the first argument won't have
        a default value or an annotation.
        """

        assert spec.startswith('($')

        pos = spec.find(',')
        if pos == -1:
            pos = spec.find(')')

        cpos = spec.find(':')
        assert cpos == -1 or cpos > pos

        cpos = spec.find('=')
        assert cpos == -1 or cpos > pos

        return spec[2:pos]

    def _signature_strip_non_python_syntax(signature):
        """
        Private helper function. Takes a signature in Argument Clinic's
        extended signature format.

        Returns a tuple of three things:
          * that signature re-rendered in standard Python syntax,
          * the index of the "self" parameter (generally 0), or None if
            the function does not have a "self" parameter, and
          * the index of the last "positional only" parameter,
            or None if the signature has no positional-only parameters.
        """

        if not signature:
            return signature, None, None

        self_parameter = None
        last_positional_only = None

        lines = [l.encode('ascii') for l in signature.split('\n')]
        generator = iter(lines).__next__
        token_stream = tokenize.tokenize(generator)

        delayed_comma = False
        skip_next_comma = False
        text = []
        add = text.append

        current_parameter = 0
        OP = token.OP
        ERRORTOKEN = token.ERRORTOKEN

        # token stream always starts with ENCODING token, skip it
        t = next(token_stream)
        assert t.type == tokenize.ENCODING

        for t in token_stream:
            type, string = t.type, t.string

            if type == OP:
                if string == ',':
                    if skip_next_comma:
                        skip_next_comma = False
                    else:
                        assert not delayed_comma
                        delayed_comma = True
                        current_parameter += 1
                    continue

                if string == '/':
                    assert not skip_next_comma
                    assert last_positional_only is None
                    skip_next_comma = True
                    last_positional_only = current_parameter - 1
                    continue

            if (type == ERRORTOKEN) and (string == '$'):
                assert self_parameter is None
                self_parameter = current_parameter
                continue

            if delayed_comma:
                delayed_comma = False
                if not ((type == OP) and (string == ')')):
                    add(', ')
            add(string)
            if (string == ','):
                add(' ')
        clean_signature = ''.join(text)
        return clean_signature, self_parameter, last_positional_only

    def _signature_fromstr(cls, obj, s, skip_bound_arg=True):
        """Private helper to parse content of '__text_signature__'
        and return a Signature based on it.
        """
        # Lazy import ast because it's relatively heavy and
        # it's not used for other than this function.
        import ast

        Parameter = cls._parameter_cls

        clean_signature, self_parameter, last_positional_only = \
            _signature_strip_non_python_syntax(s)

        program = "def foo" + clean_signature + ": pass"

        try:
            module = ast.parse(program)
        except SyntaxError:
            module = None

        if not isinstance(module, ast.Module):
            raise ValueError("{!r} builtin has invalid signature".format(obj))

        f = module.body[0]

        parameters = []
        empty = Parameter.empty
        invalid = object()

        module = None
        module_dict = {}
        module_name = getattr(obj, '__module__', None)
        if module_name:
            module = sys.modules.get(module_name, None)
            if module:
                module_dict = module.__dict__
        sys_module_dict = sys.modules.copy()

        def parse_name(node):
            assert isinstance(node, ast.arg)
            if node.annotation is not None:
                raise ValueError("Annotations are not currently supported")
            return node.arg

        def wrap_value(s):
            try:
                value = eval(s, module_dict)
            except NameError:
                try:
                    value = eval(s, sys_module_dict)
                except NameError:
                    raise RuntimeError()

            if isinstance(value, (str, int, float, bytes, bool, type(None))):
                return ast.Constant(value)
            raise RuntimeError()

        class RewriteSymbolics(ast.NodeTransformer):
            def visit_Attribute(self, node):
                a = []
                n = node
                while isinstance(n, ast.Attribute):
                    a.append(n.attr)
                    n = n.value
                if not isinstance(n, ast.Name):
                    raise RuntimeError()
                a.append(n.id)
                value = ".".join(reversed(a))
                return wrap_value(value)

            def visit_Name(self, node):
                if not isinstance(node.ctx, ast.Load):
                    raise ValueError()
                return wrap_value(node.id)

        def p(name_node, default_node, default=empty):
            name = parse_name(name_node)
            if name is invalid:
                return None
            if default_node and default_node is not _empty:
                try:
                    default_node = RewriteSymbolics().visit(default_node)
                    o = ast.literal_eval(default_node)
                except ValueError:
                    o = invalid
                if o is invalid:
                    return None
                default = o if o is not invalid else default
            parameters.append(Parameter(name, kind, default=default, annotation=empty))

        # non-keyword-only parameters
        args = reversed(f.args.args)
        defaults = reversed(f.args.defaults)
        iter = itertools.zip_longest(args, defaults, fillvalue=None)
        if last_positional_only is not None:
            kind = Parameter.POSITIONAL_ONLY
        else:
            kind = Parameter.POSITIONAL_OR_KEYWORD
        for i, (name, default) in enumerate(reversed(list(iter))):
            p(name, default)
            if i == last_positional_only:
                kind = Parameter.POSITIONAL_OR_KEYWORD

        # *args
        if f.args.vararg:
            kind = Parameter.VAR_POSITIONAL
            p(f.args.vararg, empty)

        # keyword-only arguments
        kind = Parameter.KEYWORD_ONLY
        for name, default in zip(f.args.kwonlyargs, f.args.kw_defaults):
            p(name, default)

        # **kwargs
        if f.args.kwarg:
            kind = Parameter.VAR_KEYWORD
            p(f.args.kwarg, empty)

        if self_parameter is not None:
            # Possibly strip the bound argument:
            #    - We *always* strip first bound argument if
            #      it is a module.
            #    - We don't strip first bound argument if
            #      skip_bound_arg is False.
            assert parameters
            _self = getattr(obj, '__self__', None)
            self_isbound = _self is not None
            self_ismodule = ismodule(_self)
            if self_isbound and (self_ismodule or skip_bound_arg):
                parameters.pop(0)
            else:
                # for builtins, self parameter is always positional-only!
                p = parameters[0].replace(kind=Parameter.POSITIONAL_ONLY)
                parameters[0] = p

        return cls(parameters, return_annotation=cls.empty)

    def _signature_from_builtin(cls, func, skip_bound_arg=True):
        """Private helper function to get signature for
        builtin callables.
        """

        if not _signature_is_builtin(func):
            raise TypeError("{!r} is not a Python builtin "
                            "function".format(func))

        s = getattr(func, "__text_signature__", None)
        if not s:
            raise ValueError("no signature found for builtin {!r}".format(func))

        return _signature_fromstr(cls, func, s, skip_bound_arg)

    def _signature_from_function(cls, func, skip_bound_arg=True,
                                 globals=None, locals=None, eval_str=False):
        """Private helper: constructs Signature for the given python function."""

        is_duck_function = False
        if not isfunction(func):
            if _signature_is_functionlike(func):
                is_duck_function = True
            else:
                # If it's not a pure Python function, and not a duck type
                # of pure function:
                raise TypeError('{!r} is not a Python function'.format(func))

        s = getattr(func, "__text_signature__", None)
        if s:
            return _signature_fromstr(cls, func, s, skip_bound_arg)

        Parameter = cls._parameter_cls

        # Parameter information.
        func_code = func.__code__
        pos_count = func_code.co_argcount
        arg_names = func_code.co_varnames
        posonly_count = func_code.co_posonlyargcount
        positional = arg_names[:pos_count]
        keyword_only_count = func_code.co_kwonlyargcount
        keyword_only = arg_names[pos_count:pos_count + keyword_only_count]
        annotations = get_annotations(func, globals=globals, locals=locals, eval_str=eval_str)
        defaults = func.__defaults__
        kwdefaults = func.__kwdefaults__

        if defaults:
            pos_default_count = len(defaults)
        else:
            pos_default_count = 0

        parameters = []

        non_default_count = pos_count - pos_default_count
        posonly_left = posonly_count

        # Non-keyword-only parameters w/o defaults.
        for name in positional[:non_default_count]:
            kind = _POSITIONAL_ONLY if posonly_left else _POSITIONAL_OR_KEYWORD
            annotation = annotations.get(name, _empty)
            parameters.append(Parameter(name, annotation=annotation,
                                        kind=kind))
            if posonly_left:
                posonly_left -= 1

        # ... w/ defaults.
        for offset, name in enumerate(positional[non_default_count:]):
            kind = _POSITIONAL_ONLY if posonly_left else _POSITIONAL_OR_KEYWORD
            annotation = annotations.get(name, _empty)
            parameters.append(Parameter(name, annotation=annotation,
                                        kind=kind,
                                        default=defaults[offset]))
            if posonly_left:
                posonly_left -= 1

        # *args
        if func_code.co_flags & CO_VARARGS:
            name = arg_names[pos_count + keyword_only_count]
            annotation = annotations.get(name, _empty)
            parameters.append(Parameter(name, annotation=annotation,
                                        kind=_VAR_POSITIONAL))

        # Keyword-only parameters.
        for name in keyword_only:
            default = _empty
            if kwdefaults is not None:
                default = kwdefaults.get(name, _empty)

            annotation = annotations.get(name, _empty)
            parameters.append(Parameter(name, annotation=annotation,
                                        kind=_KEYWORD_ONLY,
                                        default=default))
        # **kwargs
        if func_code.co_flags & CO_VARKEYWORDS:
            index = pos_count + keyword_only_count
            if func_code.co_flags & CO_VARARGS:
                index += 1

            name = arg_names[index]
            annotation = annotations.get(name, _empty)
            parameters.append(Parameter(name, annotation=annotation,
                                        kind=_VAR_KEYWORD))

        # Is 'func' is a pure Python function - don't validate the
        # parameters list (for correct order and defaults), it should be OK.
        return cls(parameters,
                   return_annotation=annotations.get('return', _empty),
                   __validate_parameters__=is_duck_function)

    def _signature_from_callable(obj, *,
                                 follow_wrapper_chains=True,
                                 skip_bound_arg=True,
                                 globals=None,
                                 locals=None,
                                 eval_str=False,
                                 sigcls):

        """Private helper function to get signature for arbitrary
        callable objects.
        """

        _get_signature_of = functools.partial(_signature_from_callable,
                                    follow_wrapper_chains=follow_wrapper_chains,
                                    skip_bound_arg=skip_bound_arg,
                                    globals=globals,
                                    locals=locals,
                                    sigcls=sigcls,
                                    eval_str=eval_str)

        if not callable(obj):
            raise TypeError('{!r} is not a callable object'.format(obj))

        if isinstance(obj, types.MethodType):
            # In this case we skip the first parameter of the underlying
            # function (usually `self` or `cls`).
            sig = _get_signature_of(obj.__func__)

            if skip_bound_arg:
                return _signature_bound_method(sig)
            else:
                return sig

        # Was this function wrapped by a decorator?
        if follow_wrapper_chains:
            obj = unwrap(obj, stop=(lambda f: hasattr(f, "__signature__")))
            if isinstance(obj, types.MethodType):
                # If the unwrapped object is a *method*, we might want to
                # skip its first parameter (self).
                # See test_signature_wrapped_bound_method for details.
                return _get_signature_of(obj)

        try:
            sig = obj.__signature__
        except AttributeError:
            pass
        else:
            if sig is not None:
                if not isinstance(sig, Signature):
                    raise TypeError(
                        'unexpected object {!r} in __signature__ '
                        'attribute'.format(sig))
                return sig

        try:
            partialmethod = obj._partialmethod
        except AttributeError:
            pass
        else:
            if isinstance(partialmethod, functools.partialmethod):
                # Unbound partialmethod (see functools.partialmethod)
                # This means, that we need to calculate the signature
                # as if it's a regular partial object, but taking into
                # account that the first positional argument
                # (usually `self`, or `cls`) will not be passed
                # automatically (as for boundmethods)

                wrapped_sig = _get_signature_of(partialmethod.func)

                sig = _signature_get_partial(wrapped_sig, partialmethod, (None,))
                first_wrapped_param = tuple(wrapped_sig.parameters.values())[0]
                if first_wrapped_param.kind is Parameter.VAR_POSITIONAL:
                    # First argument of the wrapped callable is `*args`, as in
                    # `partialmethod(lambda *args)`.
                    return sig
                else:
                    sig_params = tuple(sig.parameters.values())
                    assert (not sig_params or
                            first_wrapped_param is not sig_params[0])
                    new_params = (first_wrapped_param,) + sig_params
                    return sig.replace(parameters=new_params)

        if isfunction(obj) or _signature_is_functionlike(obj):
            # If it's a pure Python function, or an object that is duck type
            # of a Python function (Cython functions, for instance), then:
            return _signature_from_function(sigcls, obj,
                                            skip_bound_arg=skip_bound_arg,
                                            globals=globals, locals=locals, eval_str=eval_str)

        if _signature_is_builtin(obj):
            return _signature_from_builtin(sigcls, obj,
                                           skip_bound_arg=skip_bound_arg)

        if isinstance(obj, functools.partial):
            wrapped_sig = _get_signature_of(obj.func)
            return _signature_get_partial(wrapped_sig, obj)

        sig = None
        if isinstance(obj, type):
            # obj is a class or a metaclass

            # First, let's see if it has an overloaded __call__ defined
            # in its metaclass
            call = _signature_get_user_defined_method(type(obj), '__call__')
            if call is not None:
                sig = _get_signature_of(call)
            else:
                factory_method = None
                new = _signature_get_user_defined_method(obj, '__new__')
                init = _signature_get_user_defined_method(obj, '__init__')
                # Now we check if the 'obj' class has an own '__new__' method
                if '__new__' in obj.__dict__:
                    factory_method = new
                # or an own '__init__' method
                elif '__init__' in obj.__dict__:
                    factory_method = init
                # If not, we take inherited '__new__' or '__init__', if present
                elif new is not None:
                    factory_method = new
                elif init is not None:
                    factory_method = init

                if factory_method is not None:
                    sig = _get_signature_of(factory_method)

            if sig is None:
                # At this point we know, that `obj` is a class, with no user-
                # defined '__init__', '__new__', or class-level '__call__'

                for base in obj.__mro__[:-1]:
                    # Since '__text_signature__' is implemented as a
                    # descriptor that extracts text signature from the
                    # class docstring, if 'obj' is derived from a builtin
                    # class, its own '__text_signature__' may be 'None'.
                    # Therefore, we go through the MRO (except the last
                    # class in there, which is 'object') to find the first
                    # class with non-empty text signature.
                    try:
                        text_sig = base.__text_signature__
                    except AttributeError:
                        pass
                    else:
                        if text_sig:
                            # If 'base' class has a __text_signature__ attribute:
                            # return a signature based on it
                            return _signature_fromstr(sigcls, base, text_sig)

                # No '__text_signature__' was found for the 'obj' class.
                # Last option is to check if its '__init__' is
                # object.__init__ or type.__init__.
                if type not in obj.__mro__:
                    # We have a class (not metaclass), but no user-defined
                    # __init__ or __new__ for it
                    if (obj.__init__ is object.__init__ and
                        obj.__new__ is object.__new__):
                        # Return a signature of 'object' builtin.
                        return sigcls.from_callable(object)
                    else:
                        raise ValueError(
                            'no signature found for builtin type {!r}'.format(obj))

        elif not isinstance(obj, _NonUserDefinedCallables):
            # An object with __call__
            # We also check that the 'obj' is not an instance of
            # _WrapperDescriptor or _MethodWrapper to avoid
            # infinite recursion (and even potential segfault)
            call = _signature_get_user_defined_method(type(obj), '__call__')
            if call is not None:
                try:
                    sig = _get_signature_of(call)
                except ValueError as ex:
                    msg = 'no signature found for {!r}'.format(obj)
                    raise ValueError(msg) from ex

        if sig is not None:
            # For classes and objects we skip the first parameter of their
            # __call__, __new__, or __init__ methods
            if skip_bound_arg:
                return _signature_bound_method(sig)
            else:
                return sig

        if isinstance(obj, types.BuiltinFunctionType):
            # Raise a nicer error message for builtins
            msg = 'no signature found for builtin function {!r}'.format(obj)
            raise ValueError(msg)

        raise ValueError('callable {!r} is not supported by signature'.format(obj))

    class _void:
        """A private marker - used in Parameter & Signature."""

    class _empty:
        """Marker object for Signature.empty and Parameter.empty."""

    class _ParameterKind(enum.IntEnum):
        POSITIONAL_ONLY = 0
        POSITIONAL_OR_KEYWORD = 1
        VAR_POSITIONAL = 2
        KEYWORD_ONLY = 3
        VAR_KEYWORD = 4

        def __str__(self):
            return self._name_

        @property
        def description(self):
            return _PARAM_NAME_MAPPING[self]

    _POSITIONAL_ONLY         = _ParameterKind.POSITIONAL_ONLY
    _POSITIONAL_OR_KEYWORD   = _ParameterKind.POSITIONAL_OR_KEYWORD
    _VAR_POSITIONAL          = _ParameterKind.VAR_POSITIONAL
    _KEYWORD_ONLY            = _ParameterKind.KEYWORD_ONLY
    _VAR_KEYWORD             = _ParameterKind.VAR_KEYWORD

    _PARAM_NAME_MAPPING = {
        _POSITIONAL_ONLY: 'positional-only',
        _POSITIONAL_OR_KEYWORD: 'positional or keyword',
        _VAR_POSITIONAL: 'variadic positional',
        _KEYWORD_ONLY: 'keyword-only',
        _VAR_KEYWORD: 'variadic keyword'
    }

    class Parameter:
        """Represents a parameter in a function signature.

        Has the following public attributes:

        * name : str
            The name of the parameter as a string.
        * default : object
            The default value for the parameter if specified.  If the
            parameter has no default value, this attribute is set to
            `Parameter.empty`.
        * annotation
            The annotation for the parameter if specified.  If the
            parameter has no annotation, this attribute is set to
            `Parameter.empty`.
        * kind : str
            Describes how argument values are bound to the parameter.
            Possible values: `Parameter.POSITIONAL_ONLY`,
            `Parameter.POSITIONAL_OR_KEYWORD`, `Parameter.VAR_POSITIONAL`,
            `Parameter.KEYWORD_ONLY`, `Parameter.VAR_KEYWORD`.
        """

        __slots__ = ('_name', '_kind', '_default', '_annotation')

        POSITIONAL_ONLY         = _POSITIONAL_ONLY
        POSITIONAL_OR_KEYWORD   = _POSITIONAL_OR_KEYWORD
        VAR_POSITIONAL          = _VAR_POSITIONAL
        KEYWORD_ONLY            = _KEYWORD_ONLY
        VAR_KEYWORD             = _VAR_KEYWORD

        empty = _empty

        def __init__(self, name, kind, *, default=_empty, annotation=_empty):
            try:
                self._kind = _ParameterKind(kind)
            except ValueError:
                raise ValueError(f'value {kind!r} is not a valid Parameter.kind')
            if default is not _empty:
                if self._kind in (_VAR_POSITIONAL, _VAR_KEYWORD):
                    msg = '{} parameters cannot have default values'
                    msg = msg.format(self._kind.description)
                    raise ValueError(msg)
            self._default = default
            self._annotation = annotation

            if name is _empty:
                raise ValueError('name is a required attribute for Parameter')

            if not isinstance(name, str):
                msg = 'name must be a str, not a {}'.format(type(name).__name__)
                raise TypeError(msg)

            if name[0] == '.' and name[1:].isdigit():
                # These are implicit arguments generated by comprehensions. In
                # order to provide a friendlier interface to users, we recast
                # their name as "implicitN" and treat them as positional-only.
                # See issue 19611.
                if self._kind != _POSITIONAL_OR_KEYWORD:
                    msg = (
                        'implicit arguments must be passed as '
                        'positional or keyword arguments, not {}'
                    )
                    msg = msg.format(self._kind.description)
                    raise ValueError(msg)
                self._kind = _POSITIONAL_ONLY
                name = 'implicit{}'.format(name[1:])

            if not name.isidentifier():
                raise ValueError('{!r} is not a valid parameter name'.format(name))

            self._name = name

        def __reduce__(self):
            return (type(self),
                    (self._name, self._kind),
                    {'_default': self._default,
                     '_annotation': self._annotation})

        def __setstate__(self, state):
            self._default = state['_default']
            self._annotation = state['_annotation']

        @property
        def name(self):
            return self._name

        @property
        def default(self):
            return self._default

        @property
        def annotation(self):
            return self._annotation

        @property
        def kind(self):
            return self._kind

        def replace(self, *, name=_void, kind=_void,
                    annotation=_void, default=_void):
            """Creates a customized copy of the Parameter."""

            if name is _void:
                name = self._name

            if kind is _void:
                kind = self._kind

            if annotation is _void:
                annotation = self._annotation

            if default is _void:
                default = self._default

            return type(self)(name, kind, default=default, annotation=annotation)

        def __str__(self):
            kind = self.kind
            formatted = self._name

            # Add annotation and default value
            if self._annotation is not _empty:
                formatted = '{}: {}'.format(formatted,
                                           formatannotation(self._annotation))

            if self._default is not _empty:
                if self._annotation is not _empty:
                    formatted = '{} = {}'.format(formatted, repr(self._default))
                else:
                    formatted = '{}={}'.format(formatted, repr(self._default))

            if kind == _VAR_POSITIONAL:
                formatted = '*' + formatted
            elif kind == _VAR_KEYWORD:
                formatted = '**' + formatted

            return formatted

        def __repr__(self):
            return '<{} "{}">'.format(self.__class__.__name__, self)

        def __hash__(self):
            return hash((self.name, self.kind, self.annotation, self.default))

        def __eq__(self, other):
            if self is other:
                return True
            if not isinstance(other, Parameter):
                return NotImplemented
            return (self._name == other._name and
                    self._kind == other._kind and
                    self._default == other._default and
                    self._annotation == other._annotation)

    class BoundArguments:
        """Result of `Signature.bind` call.  Holds the mapping of arguments
        to the function's parameters.

        Has the following public attributes:

        * arguments : dict
            An ordered mutable mapping of parameters' names to arguments' values.
            Does not contain arguments' default values.
        * signature : Signature
            The Signature object that created this instance.
        * args : tuple
            Tuple of positional arguments values.
        * kwargs : dict
            Dict of keyword arguments values.
        """

        __slots__ = ('arguments', '_signature', '__weakref__')

        def __init__(self, signature, arguments):
            self.arguments = arguments
            self._signature = signature

        @property
        def signature(self):
            return self._signature

        @property
        def args(self):
            args = []
            for param_name, param in self._signature.parameters.items():
                if param.kind in (_VAR_KEYWORD, _KEYWORD_ONLY):
                    break

                try:
                    arg = self.arguments[param_name]
                except KeyError:
                    # We're done here. Other arguments
                    # will be mapped in 'BoundArguments.kwargs'
                    break
                else:
                    if param.kind == _VAR_POSITIONAL:
                        # *args
                        args.extend(arg)
                    else:
                        # plain argument
                        args.append(arg)

            return tuple(args)

        @property
        def kwargs(self):
            kwargs = {}
            kwargs_started = False
            for param_name, param in self._signature.parameters.items():
                if not kwargs_started:
                    if param.kind in (_VAR_KEYWORD, _KEYWORD_ONLY):
                        kwargs_started = True
                    else:
                        if param_name not in self.arguments:
                            kwargs_started = True
                            continue

                if not kwargs_started:
                    continue

                try:
                    arg = self.arguments[param_name]
                except KeyError:
                    pass
                else:
                    if param.kind == _VAR_KEYWORD:
                        # **kwargs
                        kwargs.update(arg)
                    else:
                        # plain keyword argument
                        kwargs[param_name] = arg

            return kwargs

        def apply_defaults(self):
            """Set default values for missing arguments.

            For variable-positional arguments (*args) the default is an
            empty tuple.

            For variable-keyword arguments (**kwargs) the default is an
            empty dict.
            """
            arguments = self.arguments
            new_arguments = []
            for name, param in self._signature.parameters.items():
                try:
                    new_arguments.append((name, arguments[name]))
                except KeyError:
                    if param.default is not _empty:
                        val = param.default
                    elif param.kind is _VAR_POSITIONAL:
                        val = ()
                    elif param.kind is _VAR_KEYWORD:
                        val = {}
                    else:
                        # This BoundArguments was likely produced by
                        # Signature.bind_partial().
                        continue
                    new_arguments.append((name, val))
            self.arguments = dict(new_arguments)

        def __eq__(self, other):
            if self is other:
                return True
            if not isinstance(other, BoundArguments):
                return NotImplemented
            return (self.signature == other.signature and
                    self.arguments == other.arguments)

        def __setstate__(self, state):
            self._signature = state['_signature']
            self.arguments = state['arguments']

        def __getstate__(self):
            return {'_signature': self._signature, 'arguments': self.arguments}

        def __repr__(self):
            args = []
            for arg, value in self.arguments.items():
                args.append('{}={!r}'.format(arg, value))
            return '<{} ({})>'.format(self.__class__.__name__, ', '.join(args))

    class Signature:
        """A Signature object represents the overall signature of a function.
        It stores a Parameter object for each parameter accepted by the
        function, as well as information specific to the function itself.

        A Signature object has the following public attributes and methods:

        * parameters : OrderedDict
            An ordered mapping of parameters' names to the corresponding
            Parameter objects (keyword-only arguments are in the same order
            as listed in `code.co_varnames`).
        * return_annotation : object
            The annotation for the return type of the function if specified.
            If the function has no annotation for its return type, this
            attribute is set to `Signature.empty`.
        * bind(*args, **kwargs) -> BoundArguments
            Creates a mapping from positional and keyword arguments to
            parameters.
        * bind_partial(*args, **kwargs) -> BoundArguments
            Creates a partial mapping from positional and keyword arguments
            to parameters (simulating 'functools.partial' behavior.)
        """

        __slots__ = ('_return_annotation', '_parameters')

        _parameter_cls = Parameter
        _bound_arguments_cls = BoundArguments

        empty = _empty

        def __init__(self, parameters=None, *, return_annotation=_empty,
                     __validate_parameters__=True):
            """Constructs Signature from the given list of Parameter
            objects and 'return_annotation'.  All arguments are optional.
            """

            if parameters is None:
                params = OrderedDict()
            else:
                if __validate_parameters__:
                    params = OrderedDict()
                    top_kind = _POSITIONAL_ONLY
                    kind_defaults = False

                    for param in parameters:
                        kind = param.kind
                        name = param.name

                        if kind < top_kind:
                            msg = (
                                'wrong parameter order: {} parameter before {} '
                                'parameter'
                            )
                            msg = msg.format(top_kind.description,
                                             kind.description)
                            raise ValueError(msg)
                        elif kind > top_kind:
                            kind_defaults = False
                            top_kind = kind

                        if kind in (_POSITIONAL_ONLY, _POSITIONAL_OR_KEYWORD):
                            if param.default is _empty:
                                if kind_defaults:
                                    # No default for this parameter, but the
                                    # previous parameter of the same kind had
                                    # a default
                                    msg = 'non-default argument follows default ' \
                                          'argument'
                                    raise ValueError(msg)
                            else:
                                # There is a default for this parameter.
                                kind_defaults = True

                        if name in params:
                            msg = 'duplicate parameter name: {!r}'.format(name)
                            raise ValueError(msg)

                        params[name] = param
                else:
                    params = OrderedDict((param.name, param) for param in parameters)

            self._parameters = types.MappingProxyType(params)
            self._return_annotation = return_annotation

        @classmethod
        def from_function(cls, func):
            """Constructs Signature for the given python function.

            Deprecated since Python 3.5, use `Signature.from_callable()`.
            """

            warnings.warn("inspect.Signature.from_function() is deprecated since "
                          "Python 3.5, use Signature.from_callable()",
                          DeprecationWarning, stacklevel=2)
            return _signature_from_function(cls, func)

        @classmethod
        def from_builtin(cls, func):
            """Constructs Signature for the given builtin function.

            Deprecated since Python 3.5, use `Signature.from_callable()`.
            """

            warnings.warn("inspect.Signature.from_builtin() is deprecated since "
                          "Python 3.5, use Signature.from_callable()",
                          DeprecationWarning, stacklevel=2)
            return _signature_from_builtin(cls, func)

        @classmethod
        def from_callable(cls, obj, *,
                          follow_wrapped=True, globals=None, locals=None, eval_str=False):
            """Constructs Signature for the given callable object."""
            return _signature_from_callable(obj, sigcls=cls,
                                            follow_wrapper_chains=follow_wrapped,
                                            globals=globals, locals=locals, eval_str=eval_str)

        @property
        def parameters(self):
            return self._parameters

        @property
        def return_annotation(self):
            return self._return_annotation

        def replace(self, *, parameters=_void, return_annotation=_void):
            """Creates a customized copy of the Signature.
            Pass 'parameters' and/or 'return_annotation' arguments
            to override them in the new copy.
            """

            if parameters is _void:
                parameters = self.parameters.values()

            if return_annotation is _void:
                return_annotation = self._return_annotation

            return type(self)(parameters,
                              return_annotation=return_annotation)

        def _hash_basis(self):
            params = tuple(param for param in self.parameters.values()
                                 if param.kind != _KEYWORD_ONLY)

            kwo_params = {param.name: param for param in self.parameters.values()
                                            if param.kind == _KEYWORD_ONLY}

            return params, kwo_params, self.return_annotation

        def __hash__(self):
            params, kwo_params, return_annotation = self._hash_basis()
            kwo_params = frozenset(kwo_params.values())
            return hash((params, kwo_params, return_annotation))

        def __eq__(self, other):
            if self is other:
                return True
            if not isinstance(other, Signature):
                return NotImplemented
            return self._hash_basis() == other._hash_basis()

        def _bind(self, args, kwargs, *, partial=False):
            """Private method. Don't use directly."""

            arguments = {}

            parameters = iter(self.parameters.values())
            parameters_ex = ()
            arg_vals = iter(args)

            while True:
                # Let's iterate through the positional arguments and corresponding
                # parameters
                try:
                    arg_val = next(arg_vals)
                except StopIteration:
                    # No more positional arguments
                    try:
                        param = next(parameters)
                    except StopIteration:
                        # No more parameters. That's it. Just need to check that
                        # we have no `kwargs` after this while loop
                        break
                    else:
                        if param.kind == _VAR_POSITIONAL:
                            # That's OK, just empty *args.  Let's start parsing
                            # kwargs
                            break
                        elif param.name in kwargs:
                            if param.kind == _POSITIONAL_ONLY:
                                msg = '{arg!r} parameter is positional only, ' \
                                      'but was passed as a keyword'
                                msg = msg.format(arg=param.name)
                                raise TypeError(msg) from None
                            parameters_ex = (param,)
                            break
                        elif (param.kind == _VAR_KEYWORD or
                                                    param.default is not _empty):
                            # That's fine too - we have a default value for this
                            # parameter.  So, lets start parsing `kwargs`, starting
                            # with the current parameter
                            parameters_ex = (param,)
                            break
                        else:
                            # No default, not VAR_KEYWORD, not VAR_POSITIONAL,
                            # not in `kwargs`
                            if partial:
                                parameters_ex = (param,)
                                break
                            else:
                                msg = 'missing a required argument: {arg!r}'
                                msg = msg.format(arg=param.name)
                                raise TypeError(msg) from None
                else:
                    # We have a positional argument to process
                    try:
                        param = next(parameters)
                    except StopIteration:
                        raise TypeError('too many positional arguments') from None
                    else:
                        if param.kind in (_VAR_KEYWORD, _KEYWORD_ONLY):
                            # Looks like we have no parameter for this positional
                            # argument
                            raise TypeError(
                                'too many positional arguments') from None

                        if param.kind == _VAR_POSITIONAL:
                            # We have an '*args'-like argument, let's fill it with
                            # all positional arguments we have left and move on to
                            # the next phase
                            values = [arg_val]
                            values.extend(arg_vals)
                            arguments[param.name] = tuple(values)
                            break

                        if param.name in kwargs and param.kind != _POSITIONAL_ONLY:
                            raise TypeError(
                                'multiple values for argument {arg!r}'.format(
                                    arg=param.name)) from None

                        arguments[param.name] = arg_val

            # Now, we iterate through the remaining parameters to process
            # keyword arguments
            kwargs_param = None
            for param in itertools.chain(parameters_ex, parameters):
                if param.kind == _VAR_KEYWORD:
                    # Memorize that we have a '**kwargs'-like parameter
                    kwargs_param = param
                    continue

                if param.kind == _VAR_POSITIONAL:
                    # Named arguments don't refer to '*args'-like parameters.
                    # We only arrive here if the positional arguments ended
                    # before reaching the last parameter before *args.
                    continue

                param_name = param.name
                try:
                    arg_val = kwargs.pop(param_name)
                except KeyError:
                    # We have no value for this parameter.  It's fine though,
                    # if it has a default value, or it is an '*args'-like
                    # parameter, left alone by the processing of positional
                    # arguments.
                    if (not partial and param.kind != _VAR_POSITIONAL and
                                                        param.default is _empty):
                        raise TypeError('missing a required argument: {arg!r}'. \
                                        format(arg=param_name)) from None

                else:
                    if param.kind == _POSITIONAL_ONLY:
                        # This should never happen in case of a properly built
                        # Signature object (but let's have this check here
                        # to ensure correct behaviour just in case)
                        raise TypeError('{arg!r} parameter is positional only, '
                                        'but was passed as a keyword'. \
                                        format(arg=param.name))

                    arguments[param_name] = arg_val

            if kwargs:
                if kwargs_param is not None:
                    # Process our '**kwargs'-like parameter
                    arguments[kwargs_param.name] = kwargs
                else:
                    raise TypeError(
                        'got an unexpected keyword argument {arg!r}'.format(
                            arg=next(iter(kwargs))))

            return self._bound_arguments_cls(self, arguments)

        def bind(self, /, *args, **kwargs):
            """Get a BoundArguments object, that maps the passed `args`
            and `kwargs` to the function's signature.  Raises `TypeError`
            if the passed arguments can not be bound.
            """
            return self._bind(args, kwargs)

        def bind_partial(self, /, *args, **kwargs):
            """Get a BoundArguments object, that partially maps the
            passed `args` and `kwargs` to the function's signature.
            Raises `TypeError` if the passed arguments can not be bound.
            """
            return self._bind(args, kwargs, partial=True)

        def __reduce__(self):
            return (type(self),
                    (tuple(self._parameters.values()),),
                    {'_return_annotation': self._return_annotation})

        def __setstate__(self, state):
            self._return_annotation = state['_return_annotation']

        def __repr__(self):
            return '<{} {}>'.format(self.__class__.__name__, self)

        def __str__(self):
            result = []
            render_pos_only_separator = False
            render_kw_only_separator = True
            for param in self.parameters.values():
                formatted = str(param)

                kind = param.kind

                if kind == _POSITIONAL_ONLY:
                    render_pos_only_separator = True
                elif render_pos_only_separator:
                    # It's not a positional-only parameter, and the flag
                    # is set to 'True' (there were pos-only params before.)
                    result.append('/')
                    render_pos_only_separator = False

                if kind == _VAR_POSITIONAL:
                    # OK, we have an '*args'-like parameter, so we won't need
                    # a '*' to separate keyword-only arguments
                    render_kw_only_separator = False
                elif kind == _KEYWORD_ONLY and render_kw_only_separator:
                    # We have a keyword-only parameter to render and we haven't
                    # rendered an '*args'-like parameter before, so add a '*'
                    # separator to the parameters list ("foo(arg1, *, arg2)" case)
                    result.append('*')
                    # This condition should be only triggered once, so
                    # reset the flag
                    render_kw_only_separator = False

                result.append(formatted)

            if render_pos_only_separator:
                # There were only positional-only parameters, hence the
                # flag was not reset to 'False'
                result.append('/')

            rendered = '({})'.format(', '.join(result))

            if self.return_annotation is not _empty:
                anno = formatannotation(self.return_annotation)
                rendered += ' -> {}'.format(anno)

            return rendered

    def signature(obj, *, follow_wrapped=True, globals=None, locals=None, eval_str=False):
        """Get a signature object for the passed callable."""
        return Signature.from_callable(obj, follow_wrapped=follow_wrapped,
                                       globals=globals, locals=locals, eval_str=eval_str)

    def _main():
        """ Logic for inspecting an object given at command line """
        import argparse
        import importlib

        parser = argparse.ArgumentParser()
        parser.add_argument(
            'object',
             help="The object to be analysed. "
                  "It supports the 'module:qualname' syntax")
        parser.add_argument(
            '-d', '--details', action='store_true',
            help='Display info about the module rather than its source code')

        args = parser.parse_args()

        target = args.object
        mod_name, has_attrs, attrs = target.partition(":")
        try:
            obj = module = importlib.import_module(mod_name)
        except Exception as exc:
            msg = "Failed to import {} ({}: {})".format(mod_name,
                                                        type(exc).__name__,
                                                        exc)
            print(msg, file=sys.stderr)
            sys.exit(2)

        if has_attrs:
            parts = attrs.split(".")
            obj = module
            for part in parts:
                obj = getattr(obj, part)

        if module.__name__ in sys.builtin_module_names:
            print("Can't get info for builtin modules.", file=sys.stderr)
            sys.exit(1)

        if args.details:
            print('Target: {}'.format(target))
            print('Origin: {}'.format(getsourcefile(module)))
            print('Cached: {}'.format(module.__cached__))
            if obj is module:
                print('Loader: {}'.format(repr(module.__loader__)))
                if hasattr(module, '__path__'):
                    print('Submodule search path: {}'.format(module.__path__))
            else:
                try:
                    __, lineno = findsource(obj)
                except Exception:
                    pass
                else:
                    print('Line: {}'.format(lineno))

            print('\n')
        else:
            print(getsource(obj))

    if __name__ == "__main__":
        _main()