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	"""
	The typing module: Support for gradual typing as defined by PEP 484.

	At large scale, the structure of the module is following:
	* Imports and exports, all public names should be explicitly added to __all__.
	* Internal helper functions: these should never be used in code outside this module.
	* _SpecialForm and its instances (special forms): Any, NoReturn, ClassVar, Union, Optional
	* Two classes whose instances can be type arguments in addition to types: ForwardRef and TypeVar
	* The core of internal generics API: _GenericAlias and _VariadicGenericAlias, the latter is
	currently only used by Tuple and Callable. All subscripted types like X[int], Union[int, str],
	etc., are instances of either of these classes.
	* The public counterpart of the generics API consists of two classes: Generic and Protocol
	(the latter is currently private, but will be made public after PEP 544 acceptance).
	* Public helper functions: get_type_hints, overload, cast, no_type_check,
	no_type_check_decorator.
	* Generic aliases for collections.abc ABCs and few additional protocols.
	* Special types: NewType, NamedTuple, TypedDict (may be added soon).
	* Wrapper submodules for re and io related types.
	"""

	import abc
	from abc import abstractmethod, abstractproperty
	import collections
	import collections.abc
	import contextlib
	import functools
	import operator
	import re as stdlib_re # Avoid confusion with the re we export.
	import sys
	import types
	from types import WrapperDescriptorType, MethodWrapperType, MethodDescriptorType

	# Please keep __all__ alphabetized within each category.
	__all__ = [
	# Super-special typing primitives.
	'Any',
	'Callable',
	'ClassVar',
	'ForwardRef',
	'Generic',
	'Optional',
	'Tuple',
	'Type',
	'TypeVar',
	'Union',

	# ABCs (from collections.abc).
	'AbstractSet', # collections.abc.Set.
	'ByteString',
	'Container',
	'ContextManager',
	'Hashable',
	'ItemsView',
	'Iterable',
	'Iterator',
	'KeysView',
	'Mapping',
	'MappingView',
	'MutableMapping',
	'MutableSequence',
	'MutableSet',
	'Sequence',
	'Sized',
	'ValuesView',
	'Awaitable',
	'AsyncIterator',
	'AsyncIterable',
	'Coroutine',
	'Collection',
	'AsyncGenerator',
	'AsyncContextManager',

	# Structural checks, a.k.a. protocols.
	'Reversible',
	'SupportsAbs',
	'SupportsBytes',
	'SupportsComplex',
	'SupportsFloat',
	'SupportsInt',
	'SupportsRound',

	# Concrete collection types.
	'ChainMap',
	'Counter',
	'Deque',
	'Dict',
	'DefaultDict',
	'List',
	'OrderedDict',
	'Set',
	'FrozenSet',
	'NamedTuple', # Not really a type.
	'Generator',

	# One-off things.
	'AnyStr',
	'cast',
	'get_type_hints',
	'NewType',
	'no_type_check',
	'no_type_check_decorator',
	'NoReturn',
	'overload',
	'Text',
	'TYPE_CHECKING',
	]

	# The pseudo-submodules 're' and 'io' are part of the public
	# namespace, but excluded from __all__ because they might stomp on
	# legitimate imports of those modules.


	def _type_check(arg, msg, is_argument=True):
	"""Check that the argument is a type, and return it (internal helper).

	As a special case, accept None and return type(None) instead. Also wrap strings
	into ForwardRef instances. Consider several corner cases, for example plain
	special forms like Union are not valid, while Union[int, str] is OK, etc.
	The msg argument is a human-readable error message, e.g::

	"Union[arg, ...]: arg should be a type."

	We append the repr() of the actual value (truncated to 100 chars).
	"""
	invalid_generic_forms = (Generic, _Protocol)
	if is_argument:
	invalid_generic_forms = invalid_generic_forms + (ClassVar, )

	if arg is None:
	return type(None)
	if isinstance(arg, str):
	return ForwardRef(arg)
	if (isinstance(arg, _GenericAlias) and
	arg.__origin__ in invalid_generic_forms):
	raise TypeError(f"{arg} is not valid as type argument")
	if (isinstance(arg, _SpecialForm) and arg not in (Any, NoReturn) or
	arg in (Generic, _Protocol)):
	raise TypeError(f"Plain {arg} is not valid as type argument")
	if isinstance(arg, (type, TypeVar, ForwardRef)):
	return arg
	if not callable(arg):
	raise TypeError(f"{msg} Got {arg!r:.100}.")
	return arg


	def _type_repr(obj):
	"""Return the repr() of an object, special-casing types (internal helper).

	If obj is a type, we return a shorter version than the default
	type.__repr__, based on the module and qualified name, which is
	typically enough to uniquely identify a type. For everything
	else, we fall back on repr(obj).
	"""
	if isinstance(obj, type):
	if obj.__module__ == 'builtins':
	return obj.__qualname__
	return f'{obj.__module__}.{obj.__qualname__}'
	if obj is ...:
	return('...')
	if isinstance(obj, types.FunctionType):
	return obj.__name__
	return repr(obj)


	def _collect_type_vars(types):
	"""Collect all type variable contained in types in order of
	first appearance (lexicographic order). For example::

	_collect_type_vars((T, List[S, T])) == (T, S)
	"""
	tvars = []
	for t in types:
	if isinstance(t, TypeVar) and t not in tvars:
	tvars.append(t)
	if isinstance(t, _GenericAlias) and not t._special:
	tvars.extend([t for t in t.__parameters__ if t not in tvars])
	return tuple(tvars)


	def _subs_tvars(tp, tvars, subs):
	"""Substitute type variables 'tvars' with substitutions 'subs'.
	These two must have the same length.
	"""
	if not isinstance(tp, _GenericAlias):
	return tp
	new_args = list(tp.__args__)
	for a, arg in enumerate(tp.__args__):
	if isinstance(arg, TypeVar):
	for i, tvar in enumerate(tvars):
	if arg == tvar:
	new_args[a] = subs[i]
	else:
	new_args[a] = _subs_tvars(arg, tvars, subs)
	if tp.__origin__ is Union:
	return Union[tuple(new_args)]
	return tp.copy_with(tuple(new_args))


	def _check_generic(cls, parameters):
	"""Check correct count for parameters of a generic cls (internal helper).
	This gives a nice error message in case of count mismatch.
	"""
	if not cls.__parameters__:
	raise TypeError(f"{cls} is not a generic class")
	alen = len(parameters)
	elen = len(cls.__parameters__)
	if alen != elen:
	raise TypeError(f"Too {'many' if alen > elen else 'few'} parameters for {cls};"
	f" actual {alen}, expected {elen}")


	def _remove_dups_flatten(parameters):
	"""An internal helper for Union creation and substitution: flatten Unions
	among parameters, then remove duplicates.
	"""
	# Flatten out Union[Union[...], ...].
	params = []
	for p in parameters:
	if isinstance(p, _GenericAlias) and p.__origin__ is Union:
	params.extend(p.__args__)
	elif isinstance(p, tuple) and len(p) > 0 and p[0] is Union:
	params.extend(p[1:])
	else:
	params.append(p)
	# Weed out strict duplicates, preserving the first of each occurrence.
	all_params = set(params)
	if len(all_params) < len(params):
	new_params = []
	for t in params:
	if t in all_params:
	new_params.append(t)
	all_params.remove(t)
	params = new_params
	assert not all_params, all_params
	return tuple(params)


	_cleanups = []


	def _tp_cache(func):
	"""Internal wrapper caching __getitem__ of generic types with a fallback to
	original function for non-hashable arguments.
	"""
	cached = functools.lru_cache()(func)
	_cleanups.append(cached.cache_clear)

	@functools.wraps(func)
	def inner(args, *kwds):
	try:
	return cached(args, *kwds)
	except TypeError:
	pass # All real errors (not unhashable args) are raised below.
	return func(args, *kwds)
	return inner


	def _eval_type(t, globalns, localns):
	"""Evaluate all forward reverences in the given type t.
	For use of globalns and localns see the docstring for get_type_hints().
	"""
	if isinstance(t, ForwardRef):
	return t._evaluate(globalns, localns)
	if isinstance(t, _GenericAlias):
	ev_args = tuple(_eval_type(a, globalns, localns) for a in t.__args__)
	if ev_args == t.__args__:
	return t
	res = t.copy_with(ev_args)
	res._special = t._special
	return res
	return t


	class _Final:
	"""Mixin to prohibit subclassing"""

	__slots__ = ('__weakref__',)

	def __init_subclass__(self, args, *kwds):
	if '_root' not in kwds:
	raise TypeError("Cannot subclass special typing classes")

	class _Immutable:
	"""Mixin to indicate that object should not be copied."""

	def __copy__(self):
	return self

	def __deepcopy__(self, memo):
	return self


	class _SpecialForm(_Final, _Immutable, _root=True):
	"""Internal indicator of special typing constructs.
	See _doc instance attribute for specific docs.
	"""

	__slots__ = ('_name', '_doc')

	def __new__(cls, args, *kwds):
	"""Constructor.

	This only exists to give a better error message in case
	someone tries to subclass a special typing object (not a good idea).
	"""
	if (len(args) == 3 and
	isinstance(args[0], str) and
	isinstance(args[1], tuple)):
	# Close enough.
	raise TypeError(f"Cannot subclass {cls!r}")
	return super().__new__(cls)

	def __init__(self, name, doc):
	self._name = name
	self._doc = doc

	def __eq__(self, other):
	if not isinstance(other, _SpecialForm):
	return NotImplemented
	return self._name == other._name

	def __hash__(self):
	return hash((self._name,))

	def __repr__(self):
	return 'typing.' + self._name

	def __reduce__(self):
	return self._name

	def __call__(self, args, *kwds):
	raise TypeError(f"Cannot instantiate {self!r}")

	def __instancecheck__(self, obj):
	raise TypeError(f"{self} cannot be used with isinstance()")

	def __subclasscheck__(self, cls):
	raise TypeError(f"{self} cannot be used with issubclass()")

	@_tp_cache
	def __getitem__(self, parameters):
	if self._name == 'ClassVar':
	item = _type_check(parameters, 'ClassVar accepts only single type.')
	return _GenericAlias(self, (item,))
	if self._name == 'Union':
	if parameters == ():
	raise TypeError("Cannot take a Union of no types.")
	if not isinstance(parameters, tuple):
	parameters = (parameters,)
	msg = "Union[arg, ...]: each arg must be a type."
	parameters = tuple(_type_check(p, msg) for p in parameters)
	parameters = _remove_dups_flatten(parameters)
	if len(parameters) == 1:
	return parameters[0]
	return _GenericAlias(self, parameters)
	if self._name == 'Optional':
	arg = _type_check(parameters, "Optional[t] requires a single type.")
	return Union[arg, type(None)]
	raise TypeError(f"{self} is not subscriptable")


	Any = _SpecialForm('Any', doc=
	"""Special type indicating an unconstrained type.

	- Any is compatible with every type.
	- Any assumed to have all methods.
	- All values assumed to be instances of Any.

	Note that all the above statements are true from the point of view of
	static type checkers. At runtime, Any should not be used with instance
	or class checks.
	""")

	NoReturn = _SpecialForm('NoReturn', doc=
	"""Special type indicating functions that never return.
	Example::

	from typing import NoReturn

	def stop() -> NoReturn:
	raise Exception('no way')

	This type is invalid in other positions, e.g., ``List[NoReturn]``
	will fail in static type checkers.
	""")

	ClassVar = _SpecialForm('ClassVar', doc=
	"""Special type construct to mark class variables.

	An annotation wrapped in ClassVar indicates that a given
	attribute is intended to be used as a class variable and
	should not be set on instances of that class. Usage::

	class Starship:
	stats: ClassVar[Dict[str, int]] = {} # class variable
	damage: int = 10 # instance variable

	ClassVar accepts only types and cannot be further subscribed.

	Note that ClassVar is not a class itself, and should not
	be used with isinstance() or issubclass().
	""")

	Union = _SpecialForm('Union', doc=
	"""Union type; Union[X, Y] means either X or Y.

	To define a union, use e.g. Union[int, str]. Details:
	- The arguments must be types and there must be at least one.
	- None as an argument is a special case and is replaced by
	type(None).
	- Unions of unions are flattened, e.g.::

	Union[Union[int, str], float] == Union[int, str, float]

	- Unions of a single argument vanish, e.g.::

	Union[int] == int # The constructor actually returns int

	- Redundant arguments are skipped, e.g.::

	Union[int, str, int] == Union[int, str]

	- When comparing unions, the argument order is ignored, e.g.::

	Union[int, str] == Union[str, int]

	- You cannot subclass or instantiate a union.
	- You can use Optional[X] as a shorthand for Union[X, None].
	""")

	Optional = _SpecialForm('Optional', doc=
	"""Optional type.

	Optional[X] is equivalent to Union[X, None].
	""")


	class ForwardRef(_Final, _root=True):
	"""Internal wrapper to hold a forward reference."""

	__slots__ = ('__forward_arg__', '__forward_code__',
	'__forward_evaluated__', '__forward_value__',
	'__forward_is_argument__')

	def __init__(self, arg, is_argument=True):
	if not isinstance(arg, str):
	raise TypeError(f"Forward reference must be a string -- got {arg!r}")
	try:
	code = compile(arg, '<string>', 'eval')
	except SyntaxError:
	raise SyntaxError(f"Forward reference must be an expression -- got {arg!r}")
	self.__forward_arg__ = arg
	self.__forward_code__ = code
	self.__forward_evaluated__ = False
	self.__forward_value__ = None
	self.__forward_is_argument__ = is_argument

	def _evaluate(self, globalns, localns):
	if not self.__forward_evaluated__ or localns is not globalns:
	if globalns is None and localns is None:
	globalns = localns = {}
	elif globalns is None:
	globalns = localns
	elif localns is None:
	localns = globalns
	self.__forward_value__ = _type_check(
	eval(self.__forward_code__, globalns, localns),
	"Forward references must evaluate to types.",
	is_argument=self.__forward_is_argument__)
	self.__forward_evaluated__ = True
	return self.__forward_value__

	def __eq__(self, other):
	if not isinstance(other, ForwardRef):
	return NotImplemented
	if self.__forward_evaluated__ and other.__forward_evaluated__:
	return (self.__forward_arg__ == other.__forward_arg__ and
	self.__forward_value__ == other.__forward_value__)
	return self.__forward_arg__ == other.__forward_arg__

	def __hash__(self):
	return hash(self.__forward_arg__)

	def __repr__(self):
	return f'ForwardRef({self.__forward_arg__!r})'


	class TypeVar(_Final, _Immutable, _root=True):
	"""Type variable.

	Usage::

	T = TypeVar('T') # Can be anything
	A = TypeVar('A', str, bytes) # Must be str or bytes

	Type variables exist primarily for the benefit of static type
	checkers. They serve as the parameters for generic types as well
	as for generic function definitions. See class Generic for more
	information on generic types. Generic functions work as follows:

	def repeat(x: T, n: int) -> List[T]:
	'''Return a list containing n references to x.'''
	return [x]*n

	def longest(x: A, y: A) -> A:
	'''Return the longest of two strings.'''
	return x if len(x) >= len(y) else y

	The latter example's signature is essentially the overloading
	of (str, str) -> str and (bytes, bytes) -> bytes. Also note
	that if the arguments are instances of some subclass of str,
	the return type is still plain str.

	At runtime, isinstance(x, T) and issubclass(C, T) will raise TypeError.

	Type variables defined with covariant=True or contravariant=True
	can be used to declare covariant or contravariant generic types.
	See PEP 484 for more details. By default generic types are invariant
	in all type variables.

	Type variables can be introspected. e.g.:

	T.__name__ == 'T'
	T.__constraints__ == ()
	T.__covariant__ == False
	T.__contravariant__ = False
	A.__constraints__ == (str, bytes)

	Note that only type variables defined in global scope can be pickled.
	"""

	__slots__ = ('__name__', '__bound__', '__constraints__',
	'__covariant__', '__contravariant__')

	def __init__(self, name, *constraints, bound=None,
	covariant=False, contravariant=False):
	self.__name__ = name
	if covariant and contravariant:
	raise ValueError("Bivariant types are not supported.")
	self.__covariant__ = bool(covariant)
	self.__contravariant__ = bool(contravariant)
	if constraints and bound is not None:
	raise TypeError("Constraints cannot be combined with bound=...")
	if constraints and len(constraints) == 1:
	raise TypeError("A single constraint is not allowed")
	msg = "TypeVar(name, constraint, ...): constraints must be types."
	self.__constraints__ = tuple(_type_check(t, msg) for t in constraints)
	if bound:
	self.__bound__ = _type_check(bound, "Bound must be a type.")
	else:
	self.__bound__ = None
	try:
	def_mod = sys._getframe(1).f_globals.get('__name__', '__main__') # for pickling
	except (AttributeError, ValueError):
	def_mod = None
	if def_mod != 'typing':
	self.__module__ = def_mod

	def __repr__(self):
	if self.__covariant__:
	prefix = '+'
	elif self.__contravariant__:
	prefix = '-'
	else:
	prefix = '~'
	return prefix + self.__name__

	def __reduce__(self):
	return self.__name__


	# Special typing constructs Union, Optional, Generic, Callable and Tuple
	# use three special attributes for internal bookkeeping of generic types:
	# * __parameters__ is a tuple of unique free type parameters of a generic
	# type, for example, Dict[T, T].__parameters__ == (T,);
	# * __origin__ keeps a reference to a type that was subscripted,
	# e.g., Union[T, int].__origin__ == Union, or the non-generic version of
	# the type.
	# * __args__ is a tuple of all arguments used in subscripting,
	# e.g., Dict[T, int].__args__ == (T, int).


	# Mapping from non-generic type names that have a generic alias in typing
	# but with a different name.
	_normalize_alias = {'list': 'List',
	'tuple': 'Tuple',
	'dict': 'Dict',
	'set': 'Set',
	'frozenset': 'FrozenSet',
	'deque': 'Deque',
	'defaultdict': 'DefaultDict',
	'type': 'Type',
	'Set': 'AbstractSet'}

	def _is_dunder(attr):
	return attr.startswith('__') and attr.endswith('__')


	class _GenericAlias(_Final, _root=True):
	"""The central part of internal API.

	This represents a generic version of type 'origin' with type arguments 'params'.
	There are two kind of these aliases: user defined and special. The special ones
	are wrappers around builtin collections and ABCs in collections.abc. These must
	have 'name' always set. If 'inst' is False, then the alias can't be instantiated,
	this is used by e.g. typing.List and typing.Dict.
	"""
	def __init__(self, origin, params, *, inst=True, special=False, name=None):
	self._inst = inst
	self._special = special
	if special and name is None:
	orig_name = origin.__name__
	name = _normalize_alias.get(orig_name, orig_name)
	self._name = name
	if not isinstance(params, tuple):
	params = (params,)
	self.__origin__ = origin
	self.__args__ = tuple(... if a is _TypingEllipsis else
	() if a is _TypingEmpty else
	a for a in params)
	self.__parameters__ = _collect_type_vars(params)
	self.__slots__ = None # This is not documented.
	if not name:
	self.__module__ = origin.__module__

	@_tp_cache
	def __getitem__(self, params):
	if self.__origin__ in (Generic, _Protocol):
	# Can't subscript Generic[...] or _Protocol[...].
	raise TypeError(f"Cannot subscript already-subscripted {self}")
	if not isinstance(params, tuple):
	params = (params,)
	msg = "Parameters to generic types must be types."
	params = tuple(_type_check(p, msg) for p in params)
	_check_generic(self, params)
	return _subs_tvars(self, self.__parameters__, params)

	def copy_with(self, params):
	# We don't copy self._special.
	return _GenericAlias(self.__origin__, params, name=self._name, inst=self._inst)

	def __repr__(self):
	if (self._name != 'Callable' or
	len(self.__args__) == 2 and self.__args__[0] is Ellipsis):
	if self._name:
	name = 'typing.' + self._name
	else:
	name = _type_repr(self.__origin__)
	if not self._special:
	args = f'[{", ".join([_type_repr(a) for a in self.__args__])}]'
	else:
	args = ''
	return (f'{name}{args}')
	if self._special:
	return 'typing.Callable'
	return (f'typing.Callable'
	f'[[{", ".join([_type_repr(a) for a in self.__args__[:-1]])}], '
	f'{_type_repr(self.__args__[-1])}]')

	def __eq__(self, other):
	if not isinstance(other, _GenericAlias):
	return NotImplemented
	if self.__origin__ != other.__origin__:
	return False
	if self.__origin__ is Union and other.__origin__ is Union:
	return frozenset(self.__args__) == frozenset(other.__args__)
	return self.__args__ == other.__args__

	def __hash__(self):
	if self.__origin__ is Union:
	return hash((Union, frozenset(self.__args__)))
	return hash((self.__origin__, self.__args__))

	def __call__(self, args, *kwargs):
	if not self._inst:
	raise TypeError(f"Type {self._name} cannot be instantiated; "
	f"use {self._name.lower()}() instead")
	result = self.__origin__(args, *kwargs)
	try:
	result.__orig_class__ = self
	except AttributeError:
	pass
	return result

	def __mro_entries__(self, bases):
	if self._name: # generic version of an ABC or built-in class
	res = []
	if self.__origin__ not in bases:
	res.append(self.__origin__)
	i = bases.index(self)
	if not any(isinstance(b, _GenericAlias) or issubclass(b, Generic)
	for b in bases[i+1:]):
	res.append(Generic)
	return tuple(res)
	if self.__origin__ is Generic:
	i = bases.index(self)
	for b in bases[i+1:]:
	if isinstance(b, _GenericAlias) and b is not self:
	return ()
	return (self.__origin__,)

	def __getattr__(self, attr):
	# We are careful for copy and pickle.
	# Also for simplicity we just don't relay all dunder names
	if '__origin__' in self.__dict__ and not _is_dunder(attr):
	return getattr(self.__origin__, attr)
	raise AttributeError(attr)

	def __setattr__(self, attr, val):
	if _is_dunder(attr) or attr in ('_name', '_inst', '_special'):
	super().__setattr__(attr, val)
	else:
	setattr(self.__origin__, attr, val)

	def __instancecheck__(self, obj):
	return self.__subclasscheck__(type(obj))

	def __subclasscheck__(self, cls):
	if self._special:
	if not isinstance(cls, _GenericAlias):
	return issubclass(cls, self.__origin__)
	if cls._special:
	return issubclass(cls.__origin__, self.__origin__)
	raise TypeError("Subscripted generics cannot be used with"
	" class and instance checks")

	def __reduce__(self):
	if self._special:
	return self._name

	if self._name:
	origin = globals()[self._name]
	else:
	origin = self.__origin__
	if (origin is Callable and
	not (len(self.__args__) == 2 and self.__args__[0] is Ellipsis)):
	args = list(self.__args__[:-1]), self.__args__[-1]
	else:
	args = tuple(self.__args__)
	if len(args) == 1 and not isinstance(args[0], tuple):
	args, = args
	return operator.getitem, (origin, args)


	class _VariadicGenericAlias(_GenericAlias, _root=True):
	"""Same as _GenericAlias above but for variadic aliases. Currently,
	this is used only by special internal aliases: Tuple and Callable.
	"""
	def __getitem__(self, params):
	if self._name != 'Callable' or not self._special:
	return self.__getitem_inner__(params)
	if not isinstance(params, tuple) or len(params) != 2:
	raise TypeError("Callable must be used as "
	"Callable[[arg, ...], result].")
	args, result = params
	if args is Ellipsis:
	params = (Ellipsis, result)
	else:
	if not isinstance(args, list):
	raise TypeError(f"Callable[args, result]: args must be a list."
	f" Got {args}")
	params = (tuple(args), result)
	return self.__getitem_inner__(params)

	@_tp_cache
	def __getitem_inner__(self, params):
	if self.__origin__ is tuple and self._special:
	if params == ():
	return self.copy_with((_TypingEmpty,))
	if not isinstance(params, tuple):
	params = (params,)
	if len(params) == 2 and params[1] is ...:
	msg = "Tuple[t, ...]: t must be a type."
	p = _type_check(params[0], msg)
	return self.copy_with((p, _TypingEllipsis))
	msg = "Tuple[t0, t1, ...]: each t must be a type."
	params = tuple(_type_check(p, msg) for p in params)
	return self.copy_with(params)
	if self.__origin__ is collections.abc.Callable and self._special:
	args, result = params
	msg = "Callable[args, result]: result must be a type."
	result = _type_check(result, msg)
	if args is Ellipsis:
	return self.copy_with((_TypingEllipsis, result))
	msg = "Callable[[arg, ...], result]: each arg must be a type."
	args = tuple(_type_check(arg, msg) for arg in args)
	params = args + (result,)
	return self.copy_with(params)
	return super().__getitem__(params)


	class Generic:
	"""Abstract base class for generic types.

	A generic type is typically declared by inheriting from
	this class parameterized with one or more type variables.
	For example, a generic mapping type might be defined as::

	class Mapping(Generic[KT, VT]):
	def __getitem__(self, key: KT) -> VT:
	...
	# Etc.

	This class can then be used as follows::

	def lookup_name(mapping: Mapping[KT, VT], key: KT, default: VT) -> VT:
	try:
	return mapping[key]
	except KeyError:
	return default
	"""
	__slots__ = ()

	def __new__(cls, args, *kwds):
	if cls is Generic:
	raise TypeError("Type Generic cannot be instantiated; "
	"it can be used only as a base class")
	if super().__new__ is object.__new__ and cls.__init__ is not object.__init__:
	obj = super().__new__(cls)
	else:
	obj = super().__new__(cls, args, *kwds)
	return obj

	@_tp_cache
	def __class_getitem__(cls, params):
	if not isinstance(params, tuple):
	params = (params,)
	if not params and cls is not Tuple:
	raise TypeError(
	f"Parameter list to {cls.__qualname__}[...] cannot be empty")
	msg = "Parameters to generic types must be types."
	params = tuple(_type_check(p, msg) for p in params)
	if cls is Generic:
	# Generic can only be subscripted with unique type variables.
	if not all(isinstance(p, TypeVar) for p in params):
	raise TypeError(
	"Parameters to Generic[...] must all be type variables")
	if len(set(params)) != len(params):
	raise TypeError(
	"Parameters to Generic[...] must all be unique")
	elif cls is _Protocol:
	# _Protocol is internal at the moment, just skip the check
	pass
	else:
	# Subscripting a regular Generic subclass.
	_check_generic(cls, params)
	return _GenericAlias(cls, params)

	def __init_subclass__(cls, args, *kwargs):
	super().__init_subclass__(args, *kwargs)
	tvars = []
	if '__orig_bases__' in cls.__dict__:
	error = Generic in cls.__orig_bases__
	else:
	error = Generic in cls.__bases__ and cls.__name__ != '_Protocol'
	if error:
	raise TypeError("Cannot inherit from plain Generic")
	if '__orig_bases__' in cls.__dict__:
	tvars = _collect_type_vars(cls.__orig_bases__)
	# Look for Generic[T1, ..., Tn].
	# If found, tvars must be a subset of it.
	# If not found, tvars is it.
	# Also check for and reject plain Generic,
	# and reject multiple Generic[...].
	gvars = None
	for base in cls.__orig_bases__:
	if (isinstance(base, _GenericAlias) and
	base.__origin__ is Generic):
	if gvars is not None:
	raise TypeError(
	"Cannot inherit from Generic[...] multiple types.")
	gvars = base.__parameters__
	if gvars is None:
	gvars = tvars
	else:
	tvarset = set(tvars)
	gvarset = set(gvars)
	if not tvarset <= gvarset:
	s_vars = ', '.join(str(t) for t in tvars if t not in gvarset)
	s_args = ', '.join(str(g) for g in gvars)
	raise TypeError(f"Some type variables ({s_vars}) are"
	f" not listed in Generic[{s_args}]")
	tvars = gvars
	cls.__parameters__ = tuple(tvars)


	class _TypingEmpty:
	"""Internal placeholder for () or []. Used by TupleMeta and CallableMeta
	to allow empty list/tuple in specific places, without allowing them
	to sneak in where prohibited.
	"""


	class _TypingEllipsis:
	"""Internal placeholder for ... (ellipsis)."""


	def cast(typ, val):
	"""Cast a value to a type.

	This returns the value unchanged. To the type checker this
	signals that the return value has the designated type, but at
	runtime we intentionally don't check anything (we want this
	to be as fast as possible).
	"""
	return val


	def _get_defaults(func):
	"""Internal helper to extract the default arguments, by name."""
	try:
	code = func.__code__
	except AttributeError:
	# Some built-in functions don't have __code__, __defaults__, etc.
	return {}
	pos_count = code.co_argcount
	arg_names = code.co_varnames
	arg_names = arg_names[:pos_count]
	defaults = func.__defaults__ or ()
	kwdefaults = func.__kwdefaults__
	res = dict(kwdefaults) if kwdefaults else {}
	pos_offset = pos_count - len(defaults)
	for name, value in zip(arg_names[pos_offset:], defaults):
	assert name not in res
	res[name] = value
	return res


	_allowed_types = (types.FunctionType, types.BuiltinFunctionType,
	types.MethodType, types.ModuleType,
	WrapperDescriptorType, MethodWrapperType, MethodDescriptorType)


	def get_type_hints(obj, globalns=None, localns=None):
	"""Return type hints for an object.

	This is often the same as obj.__annotations__, but it handles
	forward references encoded as string literals, and if necessary
	adds Optional[t] if a default value equal to None is set.

	The argument may be a module, class, method, or function. The annotations
	are returned as a dictionary. For classes, annotations include also
	inherited members.

	TypeError is raised if the argument is not of a type that can contain
	annotations, and an empty dictionary is returned if no annotations are
	present.

	BEWARE -- the behavior of globalns and localns is counterintuitive
	(unless you are familiar with how eval() and exec() work). The
	search order is locals first, then globals.

	- If no dict arguments are passed, an attempt is made to use the
	globals from obj (or the respective module's globals for classes),
	and these are also used as the locals. If the object does not appear
	to have globals, an empty dictionary is used.

	- If one dict argument is passed, it is used for both globals and
	locals.

	- If two dict arguments are passed, they specify globals and
	locals, respectively.
	"""

	if getattr(obj, '__no_type_check__', None):
	return {}
	# Classes require a special treatment.
	if isinstance(obj, type):
	hints = {}
	for base in reversed(obj.__mro__):
	if globalns is None:
	base_globals = sys.modules[base.__module__].__dict__
	else:
	base_globals = globalns
	ann = base.__dict__.get('__annotations__', {})
	for name, value in ann.items():
	if value is None:
	value = type(None)
	if isinstance(value, str):
	value = ForwardRef(value, is_argument=False)
	value = _eval_type(value, base_globals, localns)
	hints[name] = value
	return hints

	if globalns is None:
	if isinstance(obj, types.ModuleType):
	globalns = obj.__dict__
	else:
	nsobj = obj
	# Find globalns for the unwrapped object.
	while hasattr(nsobj, '__wrapped__'):
	nsobj = nsobj.__wrapped__
	globalns = getattr(nsobj, '__globals__', {})
	if localns is None:
	localns = globalns
	elif localns is None:
	localns = globalns
	hints = getattr(obj, '__annotations__', None)
	if hints is None:
	# Return empty annotations for something that _could_ have them.
	if isinstance(obj, _allowed_types):
	return {}
	else:
	raise TypeError('{!r} is not a module, class, method, '
	'or function.'.format(obj))
	defaults = _get_defaults(obj)
	hints = dict(hints)
	for name, value in hints.items():
	if value is None:
	value = type(None)
	if isinstance(value, str):
	value = ForwardRef(value)
	value = _eval_type(value, globalns, localns)
	if name in defaults and defaults[name] is None:
	value = Optional[value]
	hints[name] = value
	return hints


	def no_type_check(arg):
	"""Decorator to indicate that annotations are not type hints.

	The argument must be a class or function; if it is a class, it
	applies recursively to all methods and classes defined in that class
	(but not to methods defined in its superclasses or subclasses).

	This mutates the function(s) or class(es) in place.
	"""
	if isinstance(arg, type):
	arg_attrs = arg.__dict__.copy()
	for attr, val in arg.__dict__.items():
	if val in arg.__bases__ + (arg,):
	arg_attrs.pop(attr)
	for obj in arg_attrs.values():
	if isinstance(obj, types.FunctionType):
	obj.__no_type_check__ = True
	if isinstance(obj, type):
	no_type_check(obj)
	try:
	arg.__no_type_check__ = True
	except TypeError: # built-in classes
	pass
	return arg


	def no_type_check_decorator(decorator):
	"""Decorator to give another decorator the @no_type_check effect.

	This wraps the decorator with something that wraps the decorated
	function in @no_type_check.
	"""

	@functools.wraps(decorator)
	def wrapped_decorator(args, *kwds):
	func = decorator(args, *kwds)
	func = no_type_check(func)
	return func

	return wrapped_decorator


	def _overload_dummy(args, *kwds):
	"""Helper for @overload to raise when called."""
	raise NotImplementedError(
	"You should not call an overloaded function. "
	"A series of @overload-decorated functions "
	"outside a stub module should always be followed "
	"by an implementation that is not @overload-ed.")


	def overload(func):
	"""Decorator for overloaded functions/methods.

	In a stub file, place two or more stub definitions for the same
	function in a row, each decorated with @overload. For example:

	@overload
	def utf8(value: None) -> None: ...
	@overload
	def utf8(value: bytes) -> bytes: ...
	@overload
	def utf8(value: str) -> bytes: ...

	In a non-stub file (i.e. a regular .py file), do the same but
	follow it with an implementation. The implementation should not
	be decorated with @overload. For example:

	@overload
	def utf8(value: None) -> None: ...
	@overload
	def utf8(value: bytes) -> bytes: ...
	@overload
	def utf8(value: str) -> bytes: ...
	def utf8(value):
	# implementation goes here
	"""
	return _overload_dummy


	class _ProtocolMeta(type):
	"""Internal metaclass for _Protocol.

	This exists so _Protocol classes can be generic without deriving
	from Generic.
	"""

	def __instancecheck__(self, obj):
	if _Protocol not in self.__bases__:
	return super().__instancecheck__(obj)
	raise TypeError("Protocols cannot be used with isinstance().")

	def __subclasscheck__(self, cls):
	if not self._is_protocol:
	# No structural checks since this isn't a protocol.
	return NotImplemented

	if self is _Protocol:
	# Every class is a subclass of the empty protocol.
	return True

	# Find all attributes defined in the protocol.
	attrs = self._get_protocol_attrs()

	for attr in attrs:
	if not any(attr in d.__dict__ for d in cls.__mro__):
	return False
	return True

	def _get_protocol_attrs(self):
	# Get all Protocol base classes.
	protocol_bases = []
	for c in self.__mro__:
	if getattr(c, '_is_protocol', False) and c.__name__ != '_Protocol':
	protocol_bases.append(c)

	# Get attributes included in protocol.
	attrs = set()
	for base in protocol_bases:
	for attr in base.__dict__.keys():
	# Include attributes not defined in any non-protocol bases.
	for c in self.__mro__:
	if (c is not base and attr in c.__dict__ and
	not getattr(c, '_is_protocol', False)):
	break
	else:
	if (not attr.startswith('_abc_') and
	attr != '__abstractmethods__' and
	attr != '__annotations__' and
	attr != '__weakref__' and
	attr != '_is_protocol' and
	attr != '_gorg' and
	attr != '__dict__' and
	attr != '__args__' and
	attr != '__slots__' and
	attr != '_get_protocol_attrs' and
	attr != '__next_in_mro__' and
	attr != '__parameters__' and
	attr != '__origin__' and
	attr != '__orig_bases__' and
	attr != '__extra__' and
	attr != '__tree_hash__' and
	attr != '__module__'):
	attrs.add(attr)

	return attrs


	class _Protocol(Generic, metaclass=_ProtocolMeta):
	"""Internal base class for protocol classes.

	This implements a simple-minded structural issubclass check
	(similar but more general than the one-offs in collections.abc
	such as Hashable).
	"""

	__slots__ = ()

	_is_protocol = True

	def __class_getitem__(cls, params):
	return super().__class_getitem__(params)


	# Some unconstrained type variables. These are used by the container types.
	# (These are not for export.)
	T = TypeVar('T') # Any type.
	KT = TypeVar('KT') # Key type.
	VT = TypeVar('VT') # Value type.
	T_co = TypeVar('T_co', covariant=True) # Any type covariant containers.
	V_co = TypeVar('V_co', covariant=True) # Any type covariant containers.
	VT_co = TypeVar('VT_co', covariant=True) # Value type covariant containers.
	T_contra = TypeVar('T_contra', contravariant=True) # Ditto contravariant.
	# Internal type variable used for Type[].
	CT_co = TypeVar('CT_co', covariant=True, bound=type)

	# A useful type variable with constraints. This represents string types.
	# (This one is for export!)
	AnyStr = TypeVar('AnyStr', bytes, str)


	# Various ABCs mimicking those in collections.abc.
	def _alias(origin, params, inst=True):
	return _GenericAlias(origin, params, special=True, inst=inst)

	Hashable = _alias(collections.abc.Hashable, ()) # Not generic.
	Awaitable = _alias(collections.abc.Awaitable, T_co)
	Coroutine = _alias(collections.abc.Coroutine, (T_co, T_contra, V_co))
	AsyncIterable = _alias(collections.abc.AsyncIterable, T_co)
	AsyncIterator = _alias(collections.abc.AsyncIterator, T_co)
	Iterable = _alias(collections.abc.Iterable, T_co)
	Iterator = _alias(collections.abc.Iterator, T_co)
	Reversible = _alias(collections.abc.Reversible, T_co)
	Sized = _alias(collections.abc.Sized, ()) # Not generic.
	Container = _alias(collections.abc.Container, T_co)
	Collection = _alias(collections.abc.Collection, T_co)
	Callable = _VariadicGenericAlias(collections.abc.Callable, (), special=True)
	Callable.__doc__ = \
	"""Callable type; Callable[[int], str] is a function of (int) -> str.

	The subscription syntax must always be used with exactly two
	values: the argument list and the return type. The argument list
	must be a list of types or ellipsis; the return type must be a single type.

	There is no syntax to indicate optional or keyword arguments,
	such function types are rarely used as callback types.
	"""
	AbstractSet = _alias(collections.abc.Set, T_co)
	MutableSet = _alias(collections.abc.MutableSet, T)
	# NOTE: Mapping is only covariant in the value type.
	Mapping = _alias(collections.abc.Mapping, (KT, VT_co))
	MutableMapping = _alias(collections.abc.MutableMapping, (KT, VT))
	Sequence = _alias(collections.abc.Sequence, T_co)
	MutableSequence = _alias(collections.abc.MutableSequence, T)
	ByteString = _alias(collections.abc.ByteString, ()) # Not generic
	Tuple = _VariadicGenericAlias(tuple, (), inst=False, special=True)
	Tuple.__doc__ = \
	"""Tuple type; Tuple[X, Y] is the cross-product type of X and Y.

	Example: Tuple[T1, T2] is a tuple of two elements corresponding
	to type variables T1 and T2. Tuple[int, float, str] is a tuple
	of an int, a float and a string.

	To specify a variable-length tuple of homogeneous type, use Tuple[T, ...].
	"""
	List = _alias(list, T, inst=False)
	Deque = _alias(collections.deque, T)
	Set = _alias(set, T, inst=False)
	FrozenSet = _alias(frozenset, T_co, inst=False)
	MappingView = _alias(collections.abc.MappingView, T_co)
	KeysView = _alias(collections.abc.KeysView, KT)
	ItemsView = _alias(collections.abc.ItemsView, (KT, VT_co))
	ValuesView = _alias(collections.abc.ValuesView, VT_co)
	ContextManager = _alias(contextlib.AbstractContextManager, T_co)
	AsyncContextManager = _alias(contextlib.AbstractAsyncContextManager, T_co)
	Dict = _alias(dict, (KT, VT), inst=False)
	DefaultDict = _alias(collections.defaultdict, (KT, VT))
	OrderedDict = _alias(collections.OrderedDict, (KT, VT))
	Counter = _alias(collections.Counter, T)
	ChainMap = _alias(collections.ChainMap, (KT, VT))
	Generator = _alias(collections.abc.Generator, (T_co, T_contra, V_co))
	AsyncGenerator = _alias(collections.abc.AsyncGenerator, (T_co, T_contra))
	Type = _alias(type, CT_co, inst=False)
	Type.__doc__ = \
	"""A special construct usable to annotate class objects.

	For example, suppose we have the following classes::

	class User: ... # Abstract base for User classes
	class BasicUser(User): ...
	class ProUser(User): ...
	class TeamUser(User): ...

	And a function that takes a class argument that's a subclass of
	User and returns an instance of the corresponding class::

	U = TypeVar('U', bound=User)
	def new_user(user_class: Type[U]) -> U:
	user = user_class()
	# (Here we could write the user object to a database)
	return user

	joe = new_user(BasicUser)

	At this point the type checker knows that joe has type BasicUser.
	"""


	class SupportsInt(_Protocol):
	"""An ABC with one abstract method __int__."""
	__slots__ = ()

	@abstractmethod
	def __int__(self) -> int:
	pass


	class SupportsFloat(_Protocol):
	"""An ABC with one abstract method __float__."""
	__slots__ = ()

	@abstractmethod
	def __float__(self) -> float:
	pass


	class SupportsComplex(_Protocol):
	"""An ABC with one abstract method __complex__."""
	__slots__ = ()

	@abstractmethod
	def __complex__(self) -> complex:
	pass


	class SupportsBytes(_Protocol):
	"""An ABC with one abstract method __bytes__."""
	__slots__ = ()

	@abstractmethod
	def __bytes__(self) -> bytes:
	pass


	class SupportsAbs(_Protocol[T_co]):
	"""An ABC with one abstract method __abs__ that is covariant in its return type."""
	__slots__ = ()

	@abstractmethod
	def __abs__(self) -> T_co:
	pass


	class SupportsRound(_Protocol[T_co]):
	"""An ABC with one abstract method __round__ that is covariant in its return type."""
	__slots__ = ()

	@abstractmethod
	def __round__(self, ndigits: int = 0) -> T_co:
	pass


	def _make_nmtuple(name, types):
	msg = "NamedTuple('Name', [(f0, t0), (f1, t1), ...]); each t must be a type"
	types = [(n, _type_check(t, msg)) for n, t in types]
	nm_tpl = collections.namedtuple(name, [n for n, t in types])
	# Prior to PEP 526, only _field_types attribute was assigned.
	# Now, both __annotations__ and _field_types are used to maintain compatibility.
	nm_tpl.__annotations__ = nm_tpl._field_types = collections.OrderedDict(types)
	try:
	nm_tpl.__module__ = sys._getframe(2).f_globals.get('__name__', '__main__')
	except (AttributeError, ValueError):
	pass
	return nm_tpl


	# attributes prohibited to set in NamedTuple class syntax
	_prohibited = ('__new__', '__init__', '__slots__', '__getnewargs__',
	'_fields', '_field_defaults', '_field_types',
	'_make', '_replace', '_asdict', '_source')

	_special = ('__module__', '__name__', '__annotations__')


	class NamedTupleMeta(type):

	def __new__(cls, typename, bases, ns):
	if ns.get('_root', False):
	return super().__new__(cls, typename, bases, ns)
	types = ns.get('__annotations__', {})
	nm_tpl = _make_nmtuple(typename, types.items())
	defaults = []
	defaults_dict = {}
	for field_name in types:
	if field_name in ns:
	default_value = ns[field_name]
	defaults.append(default_value)
	defaults_dict[field_name] = default_value
	elif defaults:
	raise TypeError("Non-default namedtuple field {field_name} cannot "
	"follow default field(s) {default_names}"
	.format(field_name=field_name,
	default_names=', '.join(defaults_dict.keys())))
	nm_tpl.__new__.__annotations__ = collections.OrderedDict(types)
	nm_tpl.__new__.__defaults__ = tuple(defaults)
	nm_tpl._field_defaults = defaults_dict
	# update from user namespace without overriding special namedtuple attributes
	for key in ns:
	if key in _prohibited:
	raise AttributeError("Cannot overwrite NamedTuple attribute " + key)
	elif key not in _special and key not in nm_tpl._fields:
	setattr(nm_tpl, key, ns[key])
	return nm_tpl


	class NamedTuple(metaclass=NamedTupleMeta):
	"""Typed version of namedtuple.

	Usage in Python versions >= 3.6::

	class Employee(NamedTuple):
	name: str
	id: int

	This is equivalent to::

	Employee = collections.namedtuple('Employee', ['name', 'id'])

	The resulting class has extra __annotations__ and _field_types
	attributes, giving an ordered dict mapping field names to types.
	__annotations__ should be preferred, while _field_types
	is kept to maintain pre PEP 526 compatibility. (The field names
	are in the _fields attribute, which is part of the namedtuple
	API.) Alternative equivalent keyword syntax is also accepted::

	Employee = NamedTuple('Employee', name=str, id=int)

	In Python versions <= 3.5 use::

	Employee = NamedTuple('Employee', [('name', str), ('id', int)])
	"""
	_root = True

	def __new__(args, *kwargs):
	if not args:
	raise TypeError('NamedTuple.__new__(): not enough arguments')
	cls, *args = args # allow the "cls" keyword be passed
	if args:
	typename, *args = args # allow the "typename" keyword be passed
	elif 'typename' in kwargs:
	typename = kwargs.pop('typename')
	else:
	raise TypeError("NamedTuple.__new__() missing 1 required positional "
	"argument: 'typename'")
	if args:
	try:
	fields, = args # allow the "fields" keyword be passed
	except ValueError:
	raise TypeError(f'NamedTuple.__new__() takes from 2 to 3 '
	f'positional arguments but {len(args) + 2} '
	f'were given') from None
	elif 'fields' in kwargs and len(kwargs) == 1:
	fields = kwargs.pop('fields')
	else:
	fields = None

	if fields is None:
	fields = kwargs.items()
	elif kwargs:
	raise TypeError("Either list of fields or keywords"
	" can be provided to NamedTuple, not both")
	return _make_nmtuple(typename, fields)
	__new__.__text_signature__ = '($cls, typename, fields=None, /, **kwargs)'


	def NewType(name, tp):
	"""NewType creates simple unique types with almost zero
	runtime overhead. NewType(name, tp) is considered a subtype of tp
	by static type checkers. At runtime, NewType(name, tp) returns
	a dummy function that simply returns its argument. Usage::

	UserId = NewType('UserId', int)

	def name_by_id(user_id: UserId) -> str:
	...

	UserId('user') # Fails type check

	name_by_id(42) # Fails type check
	name_by_id(UserId(42)) # OK

	num = UserId(5) + 1 # type: int
	"""

	def new_type(x):
	return x

	new_type.__name__ = name
	new_type.__supertype__ = tp
	return new_type


	# Python-version-specific alias (Python 2: unicode; Python 3: str)
	Text = str


	# Constant that's True when type checking, but False here.
	TYPE_CHECKING = False


	class IO(Generic[AnyStr]):
	"""Generic base class for TextIO and BinaryIO.

	This is an abstract, generic version of the return of open().

	NOTE: This does not distinguish between the different possible
	classes (text vs. binary, read vs. write vs. read/write,
	append-only, unbuffered). The TextIO and BinaryIO subclasses
	below capture the distinctions between text vs. binary, which is
	pervasive in the interface; however we currently do not offer a
	way to track the other distinctions in the type system.
	"""

	__slots__ = ()

	@abstractproperty
	def mode(self) -> str:
	pass

	@abstractproperty
	def name(self) -> str:
	pass

	@abstractmethod
	def close(self) -> None:
	pass

	@abstractproperty
	def closed(self) -> bool:
	pass

	@abstractmethod
	def fileno(self) -> int:
	pass

	@abstractmethod
	def flush(self) -> None:
	pass

	@abstractmethod
	def isatty(self) -> bool:
	pass

	@abstractmethod
	def read(self, n: int = -1) -> AnyStr:
	pass

	@abstractmethod
	def readable(self) -> bool:
	pass

	@abstractmethod
	def readline(self, limit: int = -1) -> AnyStr:
	pass

	@abstractmethod
	def readlines(self, hint: int = -1) -> List[AnyStr]:
	pass

	@abstractmethod
	def seek(self, offset: int, whence: int = 0) -> int:
	pass

	@abstractmethod
	def seekable(self) -> bool:
	pass

	@abstractmethod
	def tell(self) -> int:
	pass

	@abstractmethod
	def truncate(self, size: int = None) -> int:
	pass

	@abstractmethod
	def writable(self) -> bool:
	pass

	@abstractmethod
	def write(self, s: AnyStr) -> int:
	pass

	@abstractmethod
	def writelines(self, lines: List[AnyStr]) -> None:
	pass

	@abstractmethod
	def __enter__(self) -> 'IO[AnyStr]':
	pass

	@abstractmethod
	def __exit__(self, type, value, traceback) -> None:
	pass


	class BinaryIO(IO[bytes]):
	"""Typed version of the return of open() in binary mode."""

	__slots__ = ()

	@abstractmethod
	def write(self, s: Union[bytes, bytearray]) -> int:
	pass

	@abstractmethod
	def __enter__(self) -> 'BinaryIO':
	pass


	class TextIO(IO[str]):
	"""Typed version of the return of open() in text mode."""

	__slots__ = ()

	@abstractproperty
	def buffer(self) -> BinaryIO:
	pass

	@abstractproperty
	def encoding(self) -> str:
	pass

	@abstractproperty
	def errors(self) -> Optional[str]:
	pass

	@abstractproperty
	def line_buffering(self) -> bool:
	pass

	@abstractproperty
	def newlines(self) -> Any:
	pass

	@abstractmethod
	def __enter__(self) -> 'TextIO':
	pass


	class io:
	"""Wrapper namespace for IO generic classes."""

	__all__ = ['IO', 'TextIO', 'BinaryIO']
	IO = IO
	TextIO = TextIO
	BinaryIO = BinaryIO


	io.__name__ = __name__ + '.io'
	sys.modules[io.__name__] = io

	Pattern = _alias(stdlib_re.Pattern, AnyStr)
	Match = _alias(stdlib_re.Match, AnyStr)

	class re:
	"""Wrapper namespace for re type aliases."""

	__all__ = ['Pattern', 'Match']
	Pattern = Pattern
	Match = Match


	re.__name__ = __name__ + '.re'
	sys.modules[re.__name__] = re

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