+"""
+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, Concatenate
+* Classes whose instances can be type arguments in addition to types:
+ ForwardRef, TypeVar and ParamSpec
+* 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.
+* 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.
+* Wrapper submodules for re and io related types.
+"""
+
+from abc import abstractmethod, ABCMeta
+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, GenericAlias
+
+# Please keep __all__ alphabetized within each category.
+__all__ = [
+ # Super-special typing primitives.
+ 'Annotated',
+ 'Any',
+ 'Callable',
+ 'ClassVar',
+ 'Concatenate',
+ 'Final',
+ 'ForwardRef',
+ 'Generic',
+ 'Literal',
+ 'Optional',
+ 'ParamSpec',
+ 'Protocol',
+ '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',
+ 'SupportsIndex',
+ 'SupportsInt',
+ 'SupportsRound',
+
+ # Concrete collection types.
+ 'ChainMap',
+ 'Counter',
+ 'Deque',
+ 'Dict',
+ 'DefaultDict',
+ 'List',
+ 'OrderedDict',
+ 'Set',
+ 'FrozenSet',
+ 'NamedTuple', # Not really a type.
+ 'TypedDict', # Not really a type.
+ 'Generator',
+
+ # Other concrete types.
+ 'BinaryIO',
+ 'IO',
+ 'Match',
+ 'Pattern',
+ 'TextIO',
+
+ # One-off things.
+ 'AnyStr',
+ 'cast',
+ 'final',
+ 'get_args',
+ 'get_origin',
+ 'get_type_hints',
+ 'is_typeddict',
+ 'NewType',
+ 'no_type_check',
+ 'no_type_check_decorator',
+ 'NoReturn',
+ 'overload',
+ 'ParamSpecArgs',
+ 'ParamSpecKwargs',
+ 'runtime_checkable',
+ 'Text',
+ 'TYPE_CHECKING',
+ 'TypeAlias',
+ 'TypeGuard',
+]
+
+# 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_convert(arg, module=None, *, allow_special_forms=False):
+ """For converting None to type(None), and strings to ForwardRef."""
+ if arg is None:
+ return type(None)
+ if isinstance(arg, str):
+ return ForwardRef(arg, module=module, is_class=allow_special_forms)
+ return arg
+
+
+def _type_check(arg, msg, is_argument=True, module=None, *, allow_special_forms=False):
+ """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 not allow_special_forms:
+ invalid_generic_forms += (ClassVar,)
+ if is_argument:
+ invalid_generic_forms += (Final,)
+
+ arg = _type_convert(arg, module=module, allow_special_forms=allow_special_forms)
+ if (isinstance(arg, _GenericAlias) and
+ arg.__origin__ in invalid_generic_forms):
+ raise TypeError(f"{arg} is not valid as type argument")
+ if arg in (Any, NoReturn, Final, TypeAlias):
+ return arg
+ if isinstance(arg, _SpecialForm) or arg in (Generic, Protocol):
+ raise TypeError(f"Plain {arg} is not valid as type argument")
+ if isinstance(arg, (type, TypeVar, ForwardRef, types.UnionType, ParamSpec,
+ ParamSpecArgs, ParamSpecKwargs)):
+ return arg
+ if not callable(arg):
+ raise TypeError(f"{msg} Got {arg!r:.100}.")
+ return arg
+
+
+def _is_param_expr(arg):
+ return arg is ... or isinstance(arg,
+ (tuple, list, ParamSpec, _ConcatenateGenericAlias))
+
+
+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, types.GenericAlias):
+ return 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_, typevar_types=None):
+ """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)
+ """
+ if typevar_types is None:
+ typevar_types = TypeVar
+ tvars = []
+ for t in types_:
+ if isinstance(t, typevar_types) and t not in tvars:
+ tvars.append(t)
+ if isinstance(t, (_GenericAlias, GenericAlias, types.UnionType)):
+ tvars.extend([t for t in t.__parameters__ if t not in tvars])
+ return tuple(tvars)
+
+
+def _check_generic(cls, parameters, elen):
+ """Check correct count for parameters of a generic cls (internal helper).
+ This gives a nice error message in case of count mismatch.
+ """
+ if not elen:
+ raise TypeError(f"{cls} is not a generic class")
+ alen = len(parameters)
+ if alen != elen:
+ raise TypeError(f"Too {'many' if alen > elen else 'few'} arguments for {cls};"
+ f" actual {alen}, expected {elen}")
+
+def _prepare_paramspec_params(cls, params):
+ """Prepares the parameters for a Generic containing ParamSpec
+ variables (internal helper).
+ """
+ # Special case where Z[[int, str, bool]] == Z[int, str, bool] in PEP 612.
+ if (len(cls.__parameters__) == 1
+ and params and not _is_param_expr(params[0])):
+ assert isinstance(cls.__parameters__[0], ParamSpec)
+ return (params,)
+ else:
+ _check_generic(cls, params, len(cls.__parameters__))
+ _params = []
+ # Convert lists to tuples to help other libraries cache the results.
+ for p, tvar in zip(params, cls.__parameters__):
+ if isinstance(tvar, ParamSpec) and isinstance(p, list):
+ p = tuple(p)
+ _params.append(p)
+ return tuple(_params)
+
+def _deduplicate(params):
+ # 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 params
+
+
+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, (_UnionGenericAlias, types.UnionType)):
+ 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)
+
+ return tuple(_deduplicate(params))
+
+
+def _flatten_literal_params(parameters):
+ """An internal helper for Literal creation: flatten Literals among parameters"""
+ params = []
+ for p in parameters:
+ if isinstance(p, _LiteralGenericAlias):
+ params.extend(p.__args__)
+ else:
+ params.append(p)
+ return tuple(params)
+
+
+_cleanups = []
+
+
+def _tp_cache(func=None, /, *, typed=False):
+ """Internal wrapper caching __getitem__ of generic types with a fallback to
+ original function for non-hashable arguments.
+ """
+ def decorator(func):
+ cached = functools.lru_cache(typed=typed)(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
+
+ if func is not None:
+ return decorator(func)
+
+ return decorator
+
+def _eval_type(t, globalns, localns, recursive_guard=frozenset()):
+ """Evaluate all forward references in the given type t.
+ For use of globalns and localns see the docstring for get_type_hints().
+ recursive_guard is used to prevent infinite recursion with a recursive
+ ForwardRef.
+ """
+ if isinstance(t, ForwardRef):
+ return t._evaluate(globalns, localns, recursive_guard)
+ if isinstance(t, (_GenericAlias, GenericAlias, types.UnionType)):
+ ev_args = tuple(_eval_type(a, globalns, localns, recursive_guard) for a in t.__args__)
+ if ev_args == t.__args__:
+ return t
+ if isinstance(t, GenericAlias):
+ return GenericAlias(t.__origin__, ev_args)
+ if isinstance(t, types.UnionType):
+ return functools.reduce(operator.or_, ev_args)
+ else:
+ return t.copy_with(ev_args)
+ 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."""
+ __slots__ = ()
+
+ def __copy__(self):
+ return self
+
+ def __deepcopy__(self, memo):
+ return self
+
+
+# Internal indicator of special typing constructs.
+# See __doc__ instance attribute for specific docs.
+class _SpecialForm(_Final, _root=True):
+ __slots__ = ('_name', '__doc__', '_getitem')
+
+ def __init__(self, getitem):
+ self._getitem = getitem
+ self._name = getitem.__name__
+ self.__doc__ = getitem.__doc__
+
+ def __getattr__(self, item):
+ if item in {'__name__', '__qualname__'}:
+ return self._name
+
+ raise AttributeError(item)
+
+ def __mro_entries__(self, bases):
+ raise TypeError(f"Cannot subclass {self!r}")
+
+ 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 __or__(self, other):
+ return Union[self, other]
+
+ def __ror__(self, other):
+ return Union[other, self]
+
+ 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):
+ return self._getitem(self, parameters)
+
+
+class _LiteralSpecialForm(_SpecialForm, _root=True):
+ def __getitem__(self, parameters):
+ if not isinstance(parameters, tuple):
+ parameters = (parameters,)
+ return self._getitem(self, *parameters)
+
+
+@_SpecialForm
+def Any(self, parameters):
+ """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.
+ """
+ raise TypeError(f"{self} is not subscriptable")
+
+@_SpecialForm
+def NoReturn(self, parameters):
+ """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.
+ """
+ raise TypeError(f"{self} is not subscriptable")
+
+@_SpecialForm
+def ClassVar(self, parameters):
+ """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().
+ """
+ item = _type_check(parameters, f'{self} accepts only single type.')
+ return _GenericAlias(self, (item,))
+
+@_SpecialForm
+def Final(self, parameters):
+ """Special typing construct to indicate final names to type checkers.
+
+ A final name cannot be re-assigned or overridden in a subclass.
+ For example:
+
+ MAX_SIZE: Final = 9000
+ MAX_SIZE += 1 # Error reported by type checker
+
+ class Connection:
+ TIMEOUT: Final[int] = 10
+
+ class FastConnector(Connection):
+ TIMEOUT = 1 # Error reported by type checker
+
+ There is no runtime checking of these properties.
+ """
+ item = _type_check(parameters, f'{self} accepts only single type.')
+ return _GenericAlias(self, (item,))
+
+@_SpecialForm
+def Union(self, parameters):
+ """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].
+ """
+ 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]
+ if len(parameters) == 2 and type(None) in parameters:
+ return _UnionGenericAlias(self, parameters, name="Optional")
+ return _UnionGenericAlias(self, parameters)
+
+@_SpecialForm
+def Optional(self, parameters):
+ """Optional type.
+
+ Optional[X] is equivalent to Union[X, None].
+ """
+ arg = _type_check(parameters, f"{self} requires a single type.")
+ return Union[arg, type(None)]
+
+@_LiteralSpecialForm
+@_tp_cache(typed=True)
+def Literal(self, *parameters):
+ """Special typing form to define literal types (a.k.a. value types).
+
+ This form can be used to indicate to type checkers that the corresponding
+ variable or function parameter has a value equivalent to the provided
+ literal (or one of several literals):
+
+ def validate_simple(data: Any) -> Literal[True]: # always returns True
+ ...
+
+ MODE = Literal['r', 'rb', 'w', 'wb']
+ def open_helper(file: str, mode: MODE) -> str:
+ ...
+
+ open_helper('/some/path', 'r') # Passes type check
+ open_helper('/other/path', 'typo') # Error in type checker
+
+ Literal[...] cannot be subclassed. At runtime, an arbitrary value
+ is allowed as type argument to Literal[...], but type checkers may
+ impose restrictions.
+ """
+ # There is no '_type_check' call because arguments to Literal[...] are
+ # values, not types.
+ parameters = _flatten_literal_params(parameters)
+
+ try:
+ parameters = tuple(p for p, _ in _deduplicate(list(_value_and_type_iter(parameters))))
+ except TypeError: # unhashable parameters
+ pass
+
+ return _LiteralGenericAlias(self, parameters)
+
+
+@_SpecialForm
+def TypeAlias(self, parameters):
+ """Special marker indicating that an assignment should
+ be recognized as a proper type alias definition by type
+ checkers.
+
+ For example::
+
+ Predicate: TypeAlias = Callable[..., bool]
+
+ It's invalid when used anywhere except as in the example above.
+ """
+ raise TypeError(f"{self} is not subscriptable")
+
+
+@_SpecialForm
+def Concatenate(self, parameters):
+ """Used in conjunction with ``ParamSpec`` and ``Callable`` to represent a
+ higher order function which adds, removes or transforms parameters of a
+ callable.
+
+ For example::
+
+ Callable[Concatenate[int, P], int]
+
+ See PEP 612 for detailed information.
+ """
+ if parameters == ():
+ raise TypeError("Cannot take a Concatenate of no types.")
+ if not isinstance(parameters, tuple):
+ parameters = (parameters,)
+ if not isinstance(parameters[-1], ParamSpec):
+ raise TypeError("The last parameter to Concatenate should be a "
+ "ParamSpec variable.")
+ msg = "Concatenate[arg, ...]: each arg must be a type."
+ parameters = (*(_type_check(p, msg) for p in parameters[:-1]), parameters[-1])
+ return _ConcatenateGenericAlias(self, parameters,
+ _typevar_types=(TypeVar, ParamSpec),
+ _paramspec_tvars=True)
+
+
+@_SpecialForm
+def TypeGuard(self, parameters):
+ """Special typing form used to annotate the return type of a user-defined
+ type guard function. ``TypeGuard`` only accepts a single type argument.
+ At runtime, functions marked this way should return a boolean.
+
+ ``TypeGuard`` aims to benefit *type narrowing* -- a technique used by static
+ type checkers to determine a more precise type of an expression within a
+ program's code flow. Usually type narrowing is done by analyzing
+ conditional code flow and applying the narrowing to a block of code. The
+ conditional expression here is sometimes referred to as a "type guard".
+
+ Sometimes it would be convenient to use a user-defined boolean function
+ as a type guard. Such a function should use ``TypeGuard[...]`` as its
+ return type to alert static type checkers to this intention.
+
+ Using ``-> TypeGuard`` tells the static type checker that for a given
+ function:
+
+ 1. The return value is a boolean.
+ 2. If the return value is ``True``, the type of its argument
+ is the type inside ``TypeGuard``.
+
+ For example::
+
+ def is_str(val: Union[str, float]):
+ # "isinstance" type guard
+ if isinstance(val, str):
+ # Type of ``val`` is narrowed to ``str``
+ ...
+ else:
+ # Else, type of ``val`` is narrowed to ``float``.
+ ...
+
+ Strict type narrowing is not enforced -- ``TypeB`` need not be a narrower
+ form of ``TypeA`` (it can even be a wider form) and this may lead to
+ type-unsafe results. The main reason is to allow for things like
+ narrowing ``List[object]`` to ``List[str]`` even though the latter is not
+ a subtype of the former, since ``List`` is invariant. The responsibility of
+ writing type-safe type guards is left to the user.
+
+ ``TypeGuard`` also works with type variables. For more information, see
+ PEP 647 (User-Defined Type Guards).
+ """
+ item = _type_check(parameters, f'{self} accepts only single type.')
+ return _GenericAlias(self, (item,))
+
+
+class ForwardRef(_Final, _root=True):
+ """Internal wrapper to hold a forward reference."""
+
+ __slots__ = ('__forward_arg__', '__forward_code__',
+ '__forward_evaluated__', '__forward_value__',
+ '__forward_is_argument__', '__forward_is_class__',
+ '__forward_module__')
+
+ def __init__(self, arg, is_argument=True, module=None, *, is_class=False):
+ 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
+ self.__forward_is_class__ = is_class
+ self.__forward_module__ = module
+
+ def _evaluate(self, globalns, localns, recursive_guard):
+ if self.__forward_arg__ in recursive_guard:
+ return self
+ 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
+ if self.__forward_module__ is not None:
+ globalns = getattr(
+ sys.modules.get(self.__forward_module__, None), '__dict__', globalns
+ )
+ type_ = _type_check(
+ eval(self.__forward_code__, globalns, localns),
+ "Forward references must evaluate to types.",
+ is_argument=self.__forward_is_argument__,
+ allow_special_forms=self.__forward_is_class__,
+ )
+ self.__forward_value__ = _eval_type(
+ type_, globalns, localns, recursive_guard | {self.__forward_arg__}
+ )
+ 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__ and
+ self.__forward_module__ == other.__forward_module__)
+
+ def __hash__(self):
+ return hash((self.__forward_arg__, self.__forward_module__))
+
+ def __repr__(self):
+ return f'ForwardRef({self.__forward_arg__!r})'
+
+class _TypeVarLike:
+ """Mixin for TypeVar-like types (TypeVar and ParamSpec)."""
+ def __init__(self, bound, covariant, contravariant):
+ """Used to setup TypeVars and ParamSpec's bound, covariant and
+ contravariant attributes.
+ """
+ if covariant and contravariant:
+ raise ValueError("Bivariant types are not supported.")
+ self.__covariant__ = bool(covariant)
+ self.__contravariant__ = bool(contravariant)
+ if bound:
+ self.__bound__ = _type_check(bound, "Bound must be a type.")
+ else:
+ self.__bound__ = None
+
+ def __or__(self, right):
+ return Union[self, right]
+
+ def __ror__(self, left):
+ return Union[left, self]
+
+ def __repr__(self):
+ if self.__covariant__:
+ prefix = '+'
+ elif self.__contravariant__:
+ prefix = '-'
+ else:
+ prefix = '~'
+ return prefix + self.__name__
+
+ def __reduce__(self):
+ return self.__name__
+
+
+class TypeVar( _Final, _Immutable, _TypeVarLike, _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__', '__dict__')
+
+ def __init__(self, name, *constraints, bound=None,
+ covariant=False, contravariant=False):
+ self.__name__ = name
+ super().__init__(bound, covariant, 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)
+ 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
+
+
+class ParamSpecArgs(_Final, _Immutable, _root=True):
+ """The args for a ParamSpec object.
+
+ Given a ParamSpec object P, P.args is an instance of ParamSpecArgs.
+
+ ParamSpecArgs objects have a reference back to their ParamSpec:
+
+ P.args.__origin__ is P
+
+ This type is meant for runtime introspection and has no special meaning to
+ static type checkers.
+ """
+ def __init__(self, origin):
+ self.__origin__ = origin
+
+ def __repr__(self):
+ return f"{self.__origin__.__name__}.args"
+
+ def __eq__(self, other):
+ if not isinstance(other, ParamSpecArgs):
+ return NotImplemented
+ return self.__origin__ == other.__origin__
+
+
+class ParamSpecKwargs(_Final, _Immutable, _root=True):
+ """The kwargs for a ParamSpec object.
+
+ Given a ParamSpec object P, P.kwargs is an instance of ParamSpecKwargs.
+
+ ParamSpecKwargs objects have a reference back to their ParamSpec:
+
+ P.kwargs.__origin__ is P
+
+ This type is meant for runtime introspection and has no special meaning to
+ static type checkers.
+ """
+ def __init__(self, origin):
+ self.__origin__ = origin
+
+ def __repr__(self):
+ return f"{self.__origin__.__name__}.kwargs"
+
+ def __eq__(self, other):
+ if not isinstance(other, ParamSpecKwargs):
+ return NotImplemented
+ return self.__origin__ == other.__origin__
+
+
+class ParamSpec(_Final, _Immutable, _TypeVarLike, _root=True):
+ """Parameter specification variable.
+
+ Usage::
+
+ P = ParamSpec('P')
+
+ Parameter specification variables exist primarily for the benefit of static
+ type checkers. They are used to forward the parameter types of one
+ callable to another callable, a pattern commonly found in higher order
+ functions and decorators. They are only valid when used in ``Concatenate``,
+ or as the first argument to ``Callable``, or as parameters for user-defined
+ Generics. See class Generic for more information on generic types. An
+ example for annotating a decorator::
+
+ T = TypeVar('T')
+ P = ParamSpec('P')
+
+ def add_logging(f: Callable[P, T]) -> Callable[P, T]:
+ '''A type-safe decorator to add logging to a function.'''
+ def inner(*args: P.args, **kwargs: P.kwargs) -> T:
+ logging.info(f'{f.__name__} was called')
+ return f(*args, **kwargs)
+ return inner
+
+ @add_logging
+ def add_two(x: float, y: float) -> float:
+ '''Add two numbers together.'''
+ return x + y
+
+ Parameter specification variables defined with covariant=True or
+ contravariant=True can be used to declare covariant or contravariant
+ generic types. These keyword arguments are valid, but their actual semantics
+ are yet to be decided. See PEP 612 for details.
+
+ Parameter specification variables can be introspected. e.g.:
+
+ P.__name__ == 'P'
+ P.__bound__ == None
+ P.__covariant__ == False
+ P.__contravariant__ == False
+
+ Note that only parameter specification variables defined in global scope can
+ be pickled.
+ """
+
+ __slots__ = ('__name__', '__bound__', '__covariant__', '__contravariant__',
+ '__dict__')
+
+ @property
+ def args(self):
+ return ParamSpecArgs(self)
+
+ @property
+ def kwargs(self):
+ return ParamSpecKwargs(self)
+
+ def __init__(self, name, *, bound=None, covariant=False, contravariant=False):
+ self.__name__ = name
+ super().__init__(bound, covariant, contravariant)
+ try:
+ def_mod = sys._getframe(1).f_globals.get('__name__', '__main__')
+ except (AttributeError, ValueError):
+ def_mod = None
+ if def_mod != 'typing':
+ self.__module__ = def_mod
+
+
+def _is_dunder(attr):
+ return attr.startswith('__') and attr.endswith('__')
+
+class _BaseGenericAlias(_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, *, inst=True, name=None):
+ self._inst = inst
+ self._name = name
+ self.__origin__ = origin
+ self.__slots__ = None # This is not documented.
+
+ def __call__(self, *args, **kwargs):
+ if not self._inst:
+ raise TypeError(f"Type {self._name} cannot be instantiated; "
+ f"use {self.__origin__.__name__}() instead")
+ result = self.__origin__(*args, **kwargs)
+ try:
+ result.__orig_class__ = self
+ except AttributeError:
+ pass
+ return result
+
+ def __mro_entries__(self, bases):
+ res = []
+ if self.__origin__ not in bases:
+ res.append(self.__origin__)
+ i = bases.index(self)
+ for b in bases[i+1:]:
+ if isinstance(b, _BaseGenericAlias) or issubclass(b, Generic):
+ break
+ else:
+ res.append(Generic)
+ return tuple(res)
+
+ def __getattr__(self, attr):
+ if attr in {'__name__', '__qualname__'}:
+ return self._name or self.__origin__.__name__
+
+ # We are careful for copy and pickle.
+ # Also for simplicity we don't relay any 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', '_nparams',
+ '_typevar_types', '_paramspec_tvars'}:
+ super().__setattr__(attr, val)
+ else:
+ setattr(self.__origin__, attr, val)
+
+ def __instancecheck__(self, obj):
+ return self.__subclasscheck__(type(obj))
+
+ def __subclasscheck__(self, cls):
+ raise TypeError("Subscripted generics cannot be used with"
+ " class and instance checks")
+
+ def __dir__(self):
+ return list(set(super().__dir__()
+ + [attr for attr in dir(self.__origin__) if not _is_dunder(attr)]))
+
+# 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).
+
+
+class _GenericAlias(_BaseGenericAlias, _root=True):
+ def __init__(self, origin, params, *, inst=True, name=None,
+ _typevar_types=TypeVar,
+ _paramspec_tvars=False):
+ super().__init__(origin, inst=inst, name=name)
+ if not isinstance(params, tuple):
+ params = (params,)
+ self.__args__ = tuple(... if a is _TypingEllipsis else
+ () if a is _TypingEmpty else
+ a for a in params)
+ self.__parameters__ = _collect_type_vars(params, typevar_types=_typevar_types)
+ self._typevar_types = _typevar_types
+ self._paramspec_tvars = _paramspec_tvars
+ if not name:
+ self.__module__ = origin.__module__
+
+ def __eq__(self, other):
+ if not isinstance(other, _GenericAlias):
+ return NotImplemented
+ return (self.__origin__ == other.__origin__
+ and self.__args__ == other.__args__)
+
+ def __hash__(self):
+ return hash((self.__origin__, self.__args__))
+
+ def __or__(self, right):
+ return Union[self, right]
+
+ def __ror__(self, left):
+ return Union[left, self]
+
+ @_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,)
+ params = tuple(_type_convert(p) for p in params)
+ if (self._paramspec_tvars
+ and any(isinstance(t, ParamSpec) for t in self.__parameters__)):
+ params = _prepare_paramspec_params(self, params)
+ else:
+ _check_generic(self, params, len(self.__parameters__))
+
+ subst = dict(zip(self.__parameters__, params))
+ new_args = []
+ for arg in self.__args__:
+ if isinstance(arg, self._typevar_types):
+ if isinstance(arg, ParamSpec):
+ arg = subst[arg]
+ if not _is_param_expr(arg):
+ raise TypeError(f"Expected a list of types, an ellipsis, "
+ f"ParamSpec, or Concatenate. Got {arg}")
+ else:
+ arg = subst[arg]
+ elif isinstance(arg, (_GenericAlias, GenericAlias, types.UnionType)):
+ subparams = arg.__parameters__
+ if subparams:
+ subargs = tuple(subst[x] for x in subparams)
+ arg = arg[subargs]
+ # Required to flatten out the args for CallableGenericAlias
+ if self.__origin__ == collections.abc.Callable and isinstance(arg, tuple):
+ new_args.extend(arg)
+ else:
+ new_args.append(arg)
+ return self.copy_with(tuple(new_args))
+
+ def copy_with(self, params):
+ return self.__class__(self.__origin__, params, name=self._name, inst=self._inst,
+ _typevar_types=self._typevar_types,
+ _paramspec_tvars=self._paramspec_tvars)
+
+ def __repr__(self):
+ if self._name:
+ name = 'typing.' + self._name
+ else:
+ name = _type_repr(self.__origin__)
+ args = ", ".join([_type_repr(a) for a in self.__args__])
+ return f'{name}[{args}]'
+
+ def __reduce__(self):
+ if self._name:
+ origin = globals()[self._name]
+ else:
+ origin = self.__origin__
+ args = tuple(self.__args__)
+ if len(args) == 1 and (not isinstance(args[0], tuple) or
+ origin is Tuple and not args[0]):
+ args, = args
+ return operator.getitem, (origin, args)
+
+ def __mro_entries__(self, bases):
+ if isinstance(self.__origin__, _SpecialForm):
+ raise TypeError(f"Cannot subclass {self!r}")
+
+ if self._name: # generic version of an ABC or built-in class
+ return super().__mro_entries__(bases)
+ if self.__origin__ is Generic:
+ if Protocol in bases:
+ return ()
+ i = bases.index(self)
+ for b in bases[i+1:]:
+ if isinstance(b, _BaseGenericAlias) and b is not self:
+ return ()
+ return (self.__origin__,)
+
+
+# _nparams is the number of accepted parameters, e.g. 0 for Hashable,
+# 1 for List and 2 for Dict. It may be -1 if variable number of
+# parameters are accepted (needs custom __getitem__).
+
+class _SpecialGenericAlias(_BaseGenericAlias, _root=True):
+ def __init__(self, origin, nparams, *, inst=True, name=None):
+ if name is None:
+ name = origin.__name__
+ super().__init__(origin, inst=inst, name=name)
+ self._nparams = nparams
+ if origin.__module__ == 'builtins':
+ self.__doc__ = f'A generic version of {origin.__qualname__}.'
+ else:
+ self.__doc__ = f'A generic version of {origin.__module__}.{origin.__qualname__}.'
+
+ @_tp_cache
+ def __getitem__(self, params):
+ 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, self._nparams)
+ return self.copy_with(params)
+
+ def copy_with(self, params):
+ return _GenericAlias(self.__origin__, params,
+ name=self._name, inst=self._inst)
+
+ def __repr__(self):
+ return 'typing.' + self._name
+
+ def __subclasscheck__(self, cls):
+ if isinstance(cls, _SpecialGenericAlias):
+ return issubclass(cls.__origin__, self.__origin__)
+ if not isinstance(cls, _GenericAlias):
+ return issubclass(cls, self.__origin__)
+ return super().__subclasscheck__(cls)
+
+ def __reduce__(self):
+ return self._name
+
+ def __or__(self, right):
+ return Union[self, right]
+
+ def __ror__(self, left):
+ return Union[left, self]
+
+class _CallableGenericAlias(_GenericAlias, _root=True):
+ def __repr__(self):
+ assert self._name == 'Callable'
+ args = self.__args__
+ if len(args) == 2 and _is_param_expr(args[0]):
+ return super().__repr__()
+ return (f'typing.Callable'
+ f'[[{", ".join([_type_repr(a) for a in args[:-1]])}], '
+ f'{_type_repr(args[-1])}]')
+
+ def __reduce__(self):
+ args = self.__args__
+ if not (len(args) == 2 and _is_param_expr(args[0])):
+ args = list(args[:-1]), args[-1]
+ return operator.getitem, (Callable, args)
+
+
+class _CallableType(_SpecialGenericAlias, _root=True):
+ def copy_with(self, params):
+ return _CallableGenericAlias(self.__origin__, params,
+ name=self._name, inst=self._inst,
+ _typevar_types=(TypeVar, ParamSpec),
+ _paramspec_tvars=True)
+
+ def __getitem__(self, params):
+ if not isinstance(params, tuple) or len(params) != 2:
+ raise TypeError("Callable must be used as "
+ "Callable[[arg, ...], result].")
+ args, result = params
+ # This relaxes what args can be on purpose to allow things like
+ # PEP 612 ParamSpec. Responsibility for whether a user is using
+ # Callable[...] properly is deferred to static type checkers.
+ if isinstance(args, list):
+ params = (tuple(args), result)
+ else:
+ params = (args, result)
+ return self.__getitem_inner__(params)
+
+ @_tp_cache
+ def __getitem_inner__(self, params):
+ 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))
+ if not isinstance(args, tuple):
+ args = (args,)
+ args = tuple(_type_convert(arg) for arg in args)
+ params = args + (result,)
+ return self.copy_with(params)
+
+
+class _TupleType(_SpecialGenericAlias, _root=True):
+ @_tp_cache
+ def __getitem__(self, params):
+ 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)
+
+
+class _UnionGenericAlias(_GenericAlias, _root=True):
+ def copy_with(self, params):
+ return Union[params]
+
+ def __eq__(self, other):
+ if not isinstance(other, (_UnionGenericAlias, types.UnionType)):
+ return NotImplemented
+ return set(self.__args__) == set(other.__args__)
+
+ def __hash__(self):
+ return hash(frozenset(self.__args__))
+
+ def __repr__(self):
+ args = self.__args__
+ if len(args) == 2:
+ if args[0] is type(None):
+ return f'typing.Optional[{_type_repr(args[1])}]'
+ elif args[1] is type(None):
+ return f'typing.Optional[{_type_repr(args[0])}]'
+ return super().__repr__()
+
+ def __instancecheck__(self, obj):
+ return self.__subclasscheck__(type(obj))
+
+ def __subclasscheck__(self, cls):
+ for arg in self.__args__:
+ if issubclass(cls, arg):
+ return True
+
+ def __reduce__(self):
+ func, (origin, args) = super().__reduce__()
+ return func, (Union, args)
+
+
+def _value_and_type_iter(parameters):
+ return ((p, type(p)) for p in parameters)
+
+
+class _LiteralGenericAlias(_GenericAlias, _root=True):
+
+ def __eq__(self, other):
+ if not isinstance(other, _LiteralGenericAlias):
+ return NotImplemented
+
+ return set(_value_and_type_iter(self.__args__)) == set(_value_and_type_iter(other.__args__))
+
+ def __hash__(self):
+ return hash(frozenset(_value_and_type_iter(self.__args__)))
+
+
+class _ConcatenateGenericAlias(_GenericAlias, _root=True):
+ def copy_with(self, params):
+ if isinstance(params[-1], (list, tuple)):
+ return (*params[:-1], *params[-1])
+ if isinstance(params[-1], _ConcatenateGenericAlias):
+ params = (*params[:-1], *params[-1].__args__)
+ elif not isinstance(params[-1], ParamSpec):
+ raise TypeError("The last parameter to Concatenate should be a "
+ "ParamSpec variable.")
+ return super().copy_with(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__ = ()
+ _is_protocol = False
+
+ @_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")
+ params = tuple(_type_convert(p) for p in params)
+ if cls in (Generic, Protocol):
+ # Generic and Protocol can only be subscripted with unique type variables.
+ if not all(isinstance(p, (TypeVar, ParamSpec)) for p in params):
+ raise TypeError(
+ f"Parameters to {cls.__name__}[...] must all be type variables "
+ f"or parameter specification variables.")
+ if len(set(params)) != len(params):
+ raise TypeError(
+ f"Parameters to {cls.__name__}[...] must all be unique")
+ else:
+ # Subscripting a regular Generic subclass.
+ if any(isinstance(t, ParamSpec) for t in cls.__parameters__):
+ params = _prepare_paramspec_params(cls, params)
+ else:
+ _check_generic(cls, params, len(cls.__parameters__))
+ return _GenericAlias(cls, params,
+ _typevar_types=(TypeVar, ParamSpec),
+ _paramspec_tvars=True)
+
+ 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__, (TypeVar, ParamSpec))
+ # 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 not None:
+ 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)."""
+
+
+_TYPING_INTERNALS = ['__parameters__', '__orig_bases__', '__orig_class__',
+ '_is_protocol', '_is_runtime_protocol']
+
+_SPECIAL_NAMES = ['__abstractmethods__', '__annotations__', '__dict__', '__doc__',
+ '__init__', '__module__', '__new__', '__slots__',
+ '__subclasshook__', '__weakref__', '__class_getitem__']
+
+# These special attributes will be not collected as protocol members.
+EXCLUDED_ATTRIBUTES = _TYPING_INTERNALS + _SPECIAL_NAMES + ['_MutableMapping__marker']
+
+
+def _get_protocol_attrs(cls):
+ """Collect protocol members from a protocol class objects.
+
+ This includes names actually defined in the class dictionary, as well
+ as names that appear in annotations. Special names (above) are skipped.
+ """
+ attrs = set()
+ for base in cls.__mro__[:-1]: # without object
+ if base.__name__ in ('Protocol', 'Generic'):
+ continue
+ annotations = getattr(base, '__annotations__', {})
+ for attr in list(base.__dict__.keys()) + list(annotations.keys()):
+ if not attr.startswith('_abc_') and attr not in EXCLUDED_ATTRIBUTES:
+ attrs.add(attr)
+ return attrs
+
+
+def _is_callable_members_only(cls):
+ # PEP 544 prohibits using issubclass() with protocols that have non-method members.
+ return all(callable(getattr(cls, attr, None)) for attr in _get_protocol_attrs(cls))
+
+
+def _no_init_or_replace_init(self, *args, **kwargs):
+ cls = type(self)
+
+ if cls._is_protocol:
+ raise TypeError('Protocols cannot be instantiated')
+
+ # Already using a custom `__init__`. No need to calculate correct
+ # `__init__` to call. This can lead to RecursionError. See bpo-45121.
+ if cls.__init__ is not _no_init_or_replace_init:
+ return
+
+ # Initially, `__init__` of a protocol subclass is set to `_no_init_or_replace_init`.
+ # The first instantiation of the subclass will call `_no_init_or_replace_init` which
+ # searches for a proper new `__init__` in the MRO. The new `__init__`
+ # replaces the subclass' old `__init__` (ie `_no_init_or_replace_init`). Subsequent
+ # instantiation of the protocol subclass will thus use the new
+ # `__init__` and no longer call `_no_init_or_replace_init`.
+ for base in cls.__mro__:
+ init = base.__dict__.get('__init__', _no_init_or_replace_init)
+ if init is not _no_init_or_replace_init:
+ cls.__init__ = init
+ break
+ else:
+ # should not happen
+ cls.__init__ = object.__init__
+
+ cls.__init__(self, *args, **kwargs)
+
+
+def _caller(depth=1, default='__main__'):
+ try:
+ return sys._getframe(depth + 1).f_globals.get('__name__', default)
+ except (AttributeError, ValueError): # For platforms without _getframe()
+ return None
+
+
+def _allow_reckless_class_checks(depth=3):
+ """Allow instance and class checks for special stdlib modules.
+
+ The abc and functools modules indiscriminately call isinstance() and
+ issubclass() on the whole MRO of a user class, which may contain protocols.
+ """
+ try:
+ return sys._getframe(depth).f_globals['__name__'] in ['abc', 'functools']
+ except (AttributeError, ValueError): # For platforms without _getframe().
+ return True
+
+
+_PROTO_ALLOWLIST = {
+ 'collections.abc': [
+ 'Callable', 'Awaitable', 'Iterable', 'Iterator', 'AsyncIterable',
+ 'Hashable', 'Sized', 'Container', 'Collection', 'Reversible',
+ ],
+ 'contextlib': ['AbstractContextManager', 'AbstractAsyncContextManager'],
+}
+
+
+class _ProtocolMeta(ABCMeta):
+ # This metaclass is really unfortunate and exists only because of
+ # the lack of __instancehook__.
+ def __instancecheck__(cls, instance):
+ # We need this method for situations where attributes are
+ # assigned in __init__.
+ if (
+ getattr(cls, '_is_protocol', False) and
+ not getattr(cls, '_is_runtime_protocol', False) and
+ not _allow_reckless_class_checks(depth=2)
+ ):
+ raise TypeError("Instance and class checks can only be used with"
+ " @runtime_checkable protocols")
+
+ if ((not getattr(cls, '_is_protocol', False) or
+ _is_callable_members_only(cls)) and
+ issubclass(instance.__class__, cls)):
+ return True
+ if cls._is_protocol:
+ if all(hasattr(instance, attr) and
+ # All *methods* can be blocked by setting them to None.
+ (not callable(getattr(cls, attr, None)) or
+ getattr(instance, attr) is not None)
+ for attr in _get_protocol_attrs(cls)):
+ return True
+ return super().__instancecheck__(instance)
+
+
+class Protocol(Generic, metaclass=_ProtocolMeta):
+ """Base class for protocol classes.
+
+ Protocol classes are defined as::
+
+ class Proto(Protocol):
+ def meth(self) -> int:
+ ...
+
+ Such classes are primarily used with static type checkers that recognize
+ structural subtyping (static duck-typing), for example::
+
+ class C:
+ def meth(self) -> int:
+ return 0
+
+ def func(x: Proto) -> int:
+ return x.meth()
+
+ func(C()) # Passes static type check
+
+ See PEP 544 for details. Protocol classes decorated with
+ @typing.runtime_checkable act as simple-minded runtime protocols that check
+ only the presence of given attributes, ignoring their type signatures.
+ Protocol classes can be generic, they are defined as::
+
+ class GenProto(Protocol[T]):
+ def meth(self) -> T:
+ ...
+ """
+ __slots__ = ()
+ _is_protocol = True
+ _is_runtime_protocol = False
+
+ def __init_subclass__(cls, *args, **kwargs):
+ super().__init_subclass__(*args, **kwargs)
+
+ # Determine if this is a protocol or a concrete subclass.
+ if not cls.__dict__.get('_is_protocol', False):
+ cls._is_protocol = any(b is Protocol for b in cls.__bases__)
+
+ # Set (or override) the protocol subclass hook.
+ def _proto_hook(other):
+ if not cls.__dict__.get('_is_protocol', False):
+ return NotImplemented
+
+ # First, perform various sanity checks.
+ if not getattr(cls, '_is_runtime_protocol', False):
+ if _allow_reckless_class_checks():
+ return NotImplemented
+ raise TypeError("Instance and class checks can only be used with"
+ " @runtime_checkable protocols")
+ if not _is_callable_members_only(cls):
+ if _allow_reckless_class_checks():
+ return NotImplemented
+ raise TypeError("Protocols with non-method members"
+ " don't support issubclass()")
+ if not isinstance(other, type):
+ # Same error message as for issubclass(1, int).
+ raise TypeError('issubclass() arg 1 must be a class')
+
+ # Second, perform the actual structural compatibility check.
+ for attr in _get_protocol_attrs(cls):
+ for base in other.__mro__:
+ # Check if the members appears in the class dictionary...
+ if attr in base.__dict__:
+ if base.__dict__[attr] is None:
+ return NotImplemented
+ break
+
+ # ...or in annotations, if it is a sub-protocol.
+ annotations = getattr(base, '__annotations__', {})
+ if (isinstance(annotations, collections.abc.Mapping) and
+ attr in annotations and
+ issubclass(other, Generic) and other._is_protocol):
+ break
+ else:
+ return NotImplemented
+ return True
+
+ if '__subclasshook__' not in cls.__dict__:
+ cls.__subclasshook__ = _proto_hook
+
+ # We have nothing more to do for non-protocols...
+ if not cls._is_protocol:
+ return
+
+ # ... otherwise check consistency of bases, and prohibit instantiation.
+ for base in cls.__bases__:
+ if not (base in (object, Generic) or
+ base.__module__ in _PROTO_ALLOWLIST and
+ base.__name__ in _PROTO_ALLOWLIST[base.__module__] or
+ issubclass(base, Generic) and base._is_protocol):
+ raise TypeError('Protocols can only inherit from other'
+ ' protocols, got %r' % base)
+ cls.__init__ = _no_init_or_replace_init
+
+
+class _AnnotatedAlias(_GenericAlias, _root=True):
+ """Runtime representation of an annotated type.
+
+ At its core 'Annotated[t, dec1, dec2, ...]' is an alias for the type 't'
+ with extra annotations. The alias behaves like a normal typing alias,
+ instantiating is the same as instantiating the underlying type, binding
+ it to types is also the same.
+ """
+ def __init__(self, origin, metadata):
+ if isinstance(origin, _AnnotatedAlias):
+ metadata = origin.__metadata__ + metadata
+ origin = origin.__origin__
+ super().__init__(origin, origin)
+ self.__metadata__ = metadata
+
+ def copy_with(self, params):
+ assert len(params) == 1
+ new_type = params[0]
+ return _AnnotatedAlias(new_type, self.__metadata__)
+
+ def __repr__(self):
+ return "typing.Annotated[{}, {}]".format(
+ _type_repr(self.__origin__),
+ ", ".join(repr(a) for a in self.__metadata__)
+ )
+
+ def __reduce__(self):
+ return operator.getitem, (
+ Annotated, (self.__origin__,) + self.__metadata__
+ )
+
+ def __eq__(self, other):
+ if not isinstance(other, _AnnotatedAlias):
+ return NotImplemented
+ return (self.__origin__ == other.__origin__
+ and self.__metadata__ == other.__metadata__)
+
+ def __hash__(self):
+ return hash((self.__origin__, self.__metadata__))
+
+ def __getattr__(self, attr):
+ if attr in {'__name__', '__qualname__'}:
+ return 'Annotated'
+ return super().__getattr__(attr)
+
+
+class Annotated:
+ """Add context specific metadata to a type.
+
+ Example: Annotated[int, runtime_check.Unsigned] indicates to the
+ hypothetical runtime_check module that this type is an unsigned int.
+ Every other consumer of this type can ignore this metadata and treat
+ this type as int.
+
+ The first argument to Annotated must be a valid type.
+
+ Details:
+
+ - It's an error to call `Annotated` with less than two arguments.
+ - Nested Annotated are flattened::
+
+ Annotated[Annotated[T, Ann1, Ann2], Ann3] == Annotated[T, Ann1, Ann2, Ann3]
+
+ - Instantiating an annotated type is equivalent to instantiating the
+ underlying type::
+
+ Annotated[C, Ann1](5) == C(5)
+
+ - Annotated can be used as a generic type alias::
+
+ Optimized = Annotated[T, runtime.Optimize()]
+ Optimized[int] == Annotated[int, runtime.Optimize()]
+
+ OptimizedList = Annotated[List[T], runtime.Optimize()]
+ OptimizedList[int] == Annotated[List[int], runtime.Optimize()]
+ """
+
+ __slots__ = ()
+
+ def __new__(cls, *args, **kwargs):
+ raise TypeError("Type Annotated cannot be instantiated.")
+
+ @_tp_cache
+ def __class_getitem__(cls, params):
+ if not isinstance(params, tuple) or len(params) < 2:
+ raise TypeError("Annotated[...] should be used "
+ "with at least two arguments (a type and an "
+ "annotation).")
+ msg = "Annotated[t, ...]: t must be a type."
+ origin = _type_check(params[0], msg, allow_special_forms=True)
+ metadata = tuple(params[1:])
+ return _AnnotatedAlias(origin, metadata)
+
+ def __init_subclass__(cls, *args, **kwargs):
+ raise TypeError(
+ "Cannot subclass {}.Annotated".format(cls.__module__)
+ )
+
+
+def runtime_checkable(cls):
+ """Mark a protocol class as a runtime protocol.
+
+ Such protocol can be used with isinstance() and issubclass().
+ Raise TypeError if applied to a non-protocol class.
+ This allows a simple-minded structural check very similar to
+ one trick ponies in collections.abc such as Iterable.
+ For example::
+
+ @runtime_checkable
+ class Closable(Protocol):
+ def close(self): ...
+
+ assert isinstance(open('/some/file'), Closable)
+
+ Warning: this will check only the presence of the required methods,
+ not their type signatures!
+ """
+ if not issubclass(cls, Generic) or not cls._is_protocol:
+ raise TypeError('@runtime_checkable can be only applied to protocol classes,'
+ ' got %r' % cls)
+ cls._is_runtime_protocol = True
+ return cls
+
+
+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, include_extras=False):
+ """Return type hints for an object.
+
+ This is often the same as obj.__annotations__, but it handles
+ forward references encoded as string literals, adds Optional[t] if a
+ default value equal to None is set and recursively replaces all
+ 'Annotated[T, ...]' with 'T' (unless 'include_extras=True').
+
+ 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. For classes, the search
+ order is globals first then locals.
+
+ - 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 = getattr(sys.modules.get(base.__module__, None), '__dict__', {})
+ else:
+ base_globals = globalns
+ ann = base.__dict__.get('__annotations__', {})
+ if isinstance(ann, types.GetSetDescriptorType):
+ ann = {}
+ base_locals = dict(vars(base)) if localns is None else localns
+ if localns is None and globalns is None:
+ # This is surprising, but required. Before Python 3.10,
+ # get_type_hints only evaluated the globalns of
+ # a class. To maintain backwards compatibility, we reverse
+ # the globalns and localns order so that eval() looks into
+ # *base_globals* first rather than *base_locals*.
+ # This only affects ForwardRefs.
+ base_globals, base_locals = base_locals, base_globals
+ for name, value in ann.items():
+ if value is None:
+ value = type(None)
+ if isinstance(value, str):
+ value = ForwardRef(value, is_argument=False, is_class=True)
+ value = _eval_type(value, base_globals, base_locals)
+ hints[name] = value
+ return hints if include_extras else {k: _strip_annotations(t) for k, t in hints.items()}
+
+ 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):
+ # class-level forward refs were handled above, this must be either
+ # a module-level annotation or a function argument annotation
+ value = ForwardRef(
+ value,
+ is_argument=not isinstance(obj, types.ModuleType),
+ is_class=False,
+ )
+ value = _eval_type(value, globalns, localns)
+ if name in defaults and defaults[name] is None:
+ value = Optional[value]
+ hints[name] = value
+ return hints if include_extras else {k: _strip_annotations(t) for k, t in hints.items()}
+
+
+def _strip_annotations(t):
+ """Strips the annotations from a given type.
+ """
+ if isinstance(t, _AnnotatedAlias):
+ return _strip_annotations(t.__origin__)
+ if isinstance(t, _GenericAlias):
+ stripped_args = tuple(_strip_annotations(a) for a in t.__args__)
+ if stripped_args == t.__args__:
+ return t
+ return t.copy_with(stripped_args)
+ if isinstance(t, GenericAlias):
+ stripped_args = tuple(_strip_annotations(a) for a in t.__args__)
+ if stripped_args == t.__args__:
+ return t
+ return GenericAlias(t.__origin__, stripped_args)
+ if isinstance(t, types.UnionType):
+ stripped_args = tuple(_strip_annotations(a) for a in t.__args__)
+ if stripped_args == t.__args__:
+ return t
+ return functools.reduce(operator.or_, stripped_args)
+
+ return t
+
+
+def get_origin(tp):
+ """Get the unsubscripted version of a type.
+
+ This supports generic types, Callable, Tuple, Union, Literal, Final, ClassVar
+ and Annotated. Return None for unsupported types. Examples::
+
+ get_origin(Literal[42]) is Literal
+ get_origin(int) is None
+ get_origin(ClassVar[int]) is ClassVar
+ get_origin(Generic) is Generic
+ get_origin(Generic[T]) is Generic
+ get_origin(Union[T, int]) is Union
+ get_origin(List[Tuple[T, T]][int]) == list
+ get_origin(P.args) is P
+ """
+ if isinstance(tp, _AnnotatedAlias):
+ return Annotated
+ if isinstance(tp, (_BaseGenericAlias, GenericAlias,
+ ParamSpecArgs, ParamSpecKwargs)):
+ return tp.__origin__
+ if tp is Generic:
+ return Generic
+ if isinstance(tp, types.UnionType):
+ return types.UnionType
+ return None
+
+
+def get_args(tp):
+ """Get type arguments with all substitutions performed.
+
+ For unions, basic simplifications used by Union constructor are performed.
+ Examples::
+ get_args(Dict[str, int]) == (str, int)
+ get_args(int) == ()
+ get_args(Union[int, Union[T, int], str][int]) == (int, str)
+ get_args(Union[int, Tuple[T, int]][str]) == (int, Tuple[str, int])
+ get_args(Callable[[], T][int]) == ([], int)
+ """
+ if isinstance(tp, _AnnotatedAlias):
+ return (tp.__origin__,) + tp.__metadata__
+ if isinstance(tp, (_GenericAlias, GenericAlias)):
+ res = tp.__args__
+ if (tp.__origin__ is collections.abc.Callable
+ and not (len(res) == 2 and _is_param_expr(res[0]))):
+ res = (list(res[:-1]), res[-1])
+ return res
+ if isinstance(tp, types.UnionType):
+ return tp.__args__
+ return ()
+
+
+def is_typeddict(tp):
+ """Check if an annotation is a TypedDict class
+
+ For example::
+ class Film(TypedDict):
+ title: str
+ year: int
+
+ is_typeddict(Film) # => True
+ is_typeddict(Union[list, str]) # => False
+ """
+ return isinstance(tp, _TypedDictMeta)
+
+
+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
+
+
+def final(f):
+ """A decorator to indicate final methods and final classes.
+
+ Use this decorator to indicate to type checkers that the decorated
+ method cannot be overridden, and decorated class cannot be subclassed.
+ For example:
+
+ class Base:
+ @final
+ def done(self) -> None:
+ ...
+ class Sub(Base):
+ def done(self) -> None: # Error reported by type checker
+ ...
+
+ @final
+ class Leaf:
+ ...
+ class Other(Leaf): # Error reported by type checker
+ ...
+
+ There is no runtime checking of these properties.
+ """
+ return f
+
+
+# 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.
+_alias = _SpecialGenericAlias
+
+Hashable = _alias(collections.abc.Hashable, 0) # Not generic.
+Awaitable = _alias(collections.abc.Awaitable, 1)
+Coroutine = _alias(collections.abc.Coroutine, 3)
+AsyncIterable = _alias(collections.abc.AsyncIterable, 1)
+AsyncIterator = _alias(collections.abc.AsyncIterator, 1)
+Iterable = _alias(collections.abc.Iterable, 1)
+Iterator = _alias(collections.abc.Iterator, 1)
+Reversible = _alias(collections.abc.Reversible, 1)
+Sized = _alias(collections.abc.Sized, 0) # Not generic.
+Container = _alias(collections.abc.Container, 1)
+Collection = _alias(collections.abc.Collection, 1)
+Callable = _CallableType(collections.abc.Callable, 2)
+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, 1, name='AbstractSet')
+MutableSet = _alias(collections.abc.MutableSet, 1)
+# NOTE: Mapping is only covariant in the value type.
+Mapping = _alias(collections.abc.Mapping, 2)
+MutableMapping = _alias(collections.abc.MutableMapping, 2)
+Sequence = _alias(collections.abc.Sequence, 1)
+MutableSequence = _alias(collections.abc.MutableSequence, 1)
+ByteString = _alias(collections.abc.ByteString, 0) # Not generic
+# Tuple accepts variable number of parameters.
+Tuple = _TupleType(tuple, -1, inst=False, name='Tuple')
+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, 1, inst=False, name='List')
+Deque = _alias(collections.deque, 1, name='Deque')
+Set = _alias(set, 1, inst=False, name='Set')
+FrozenSet = _alias(frozenset, 1, inst=False, name='FrozenSet')
+MappingView = _alias(collections.abc.MappingView, 1)
+KeysView = _alias(collections.abc.KeysView, 1)
+ItemsView = _alias(collections.abc.ItemsView, 2)
+ValuesView = _alias(collections.abc.ValuesView, 1)
+ContextManager = _alias(contextlib.AbstractContextManager, 1, name='ContextManager')
+AsyncContextManager = _alias(contextlib.AbstractAsyncContextManager, 1, name='AsyncContextManager')
+Dict = _alias(dict, 2, inst=False, name='Dict')
+DefaultDict = _alias(collections.defaultdict, 2, name='DefaultDict')
+OrderedDict = _alias(collections.OrderedDict, 2)
+Counter = _alias(collections.Counter, 1)
+ChainMap = _alias(collections.ChainMap, 2)
+Generator = _alias(collections.abc.Generator, 3)
+AsyncGenerator = _alias(collections.abc.AsyncGenerator, 2)
+Type = _alias(type, 1, inst=False, name='Type')
+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.
+ """
+
+
+@runtime_checkable
+class SupportsInt(Protocol):
+ """An ABC with one abstract method __int__."""
+ __slots__ = ()
+
+ @abstractmethod
+ def __int__(self) -> int:
+ pass
+
+
+@runtime_checkable
+class SupportsFloat(Protocol):
+ """An ABC with one abstract method __float__."""
+ __slots__ = ()
+
+ @abstractmethod
+ def __float__(self) -> float:
+ pass
+
+
+@runtime_checkable
+class SupportsComplex(Protocol):
+ """An ABC with one abstract method __complex__."""
+ __slots__ = ()
+
+ @abstractmethod
+ def __complex__(self) -> complex:
+ pass
+
+
+@runtime_checkable
+class SupportsBytes(Protocol):
+ """An ABC with one abstract method __bytes__."""
+ __slots__ = ()
+
+ @abstractmethod
+ def __bytes__(self) -> bytes:
+ pass
+
+
+@runtime_checkable
+class SupportsIndex(Protocol):
+ """An ABC with one abstract method __index__."""
+ __slots__ = ()
+
+ @abstractmethod
+ def __index__(self) -> int:
+ pass
+
+
+@runtime_checkable
+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
+
+
+@runtime_checkable
+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, module, defaults = ()):
+ fields = [n for n, t in types]
+ types = {n: _type_check(t, f"field {n} annotation must be a type")
+ for n, t in types}
+ nm_tpl = collections.namedtuple(name, fields,
+ defaults=defaults, module=module)
+ nm_tpl.__annotations__ = nm_tpl.__new__.__annotations__ = types
+ return nm_tpl
+
+
+# attributes prohibited to set in NamedTuple class syntax
+_prohibited = frozenset({'__new__', '__init__', '__slots__', '__getnewargs__',
+ '_fields', '_field_defaults',
+ '_make', '_replace', '_asdict', '_source'})
+
+_special = frozenset({'__module__', '__name__', '__annotations__'})
+
+
+class NamedTupleMeta(type):
+
+ def __new__(cls, typename, bases, ns):
+ assert bases[0] is _NamedTuple
+ types = ns.get('__annotations__', {})
+ default_names = []
+ for field_name in types:
+ if field_name in ns:
+ default_names.append(field_name)
+ elif default_names:
+ raise TypeError(f"Non-default namedtuple field {field_name} "
+ f"cannot follow default field"
+ f"{'s' if len(default_names) > 1 else ''} "
+ f"{', '.join(default_names)}")
+ nm_tpl = _make_nmtuple(typename, types.items(),
+ defaults=[ns[n] for n in default_names],
+ module=ns['__module__'])
+ # 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
+
+
+def NamedTuple(typename, fields=None, /, **kwargs):
+ """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 an extra __annotations__ attribute, giving a
+ dict that maps field names to types. (The field names are also 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)])
+ """
+ if fields is None:
+ fields = kwargs.items()
+ elif kwargs:
+ raise TypeError("Either list of fields or keywords"
+ " can be provided to NamedTuple, not both")
+ try:
+ module = sys._getframe(1).f_globals.get('__name__', '__main__')
+ except (AttributeError, ValueError):
+ module = None
+ return _make_nmtuple(typename, fields, module=module)
+
+_NamedTuple = type.__new__(NamedTupleMeta, 'NamedTuple', (), {})
+
+def _namedtuple_mro_entries(bases):
+ if len(bases) > 1:
+ raise TypeError("Multiple inheritance with NamedTuple is not supported")
+ assert bases[0] is NamedTuple
+ return (_NamedTuple,)
+
+NamedTuple.__mro_entries__ = _namedtuple_mro_entries
+
+
+class _TypedDictMeta(type):
+ def __new__(cls, name, bases, ns, total=True):
+ """Create new typed dict class object.
+
+ This method is called when TypedDict is subclassed,
+ or when TypedDict is instantiated. This way
+ TypedDict supports all three syntax forms described in its docstring.
+ Subclasses and instances of TypedDict return actual dictionaries.
+ """
+ for base in bases:
+ if type(base) is not _TypedDictMeta:
+ raise TypeError('cannot inherit from both a TypedDict type '
+ 'and a non-TypedDict base class')
+ tp_dict = type.__new__(_TypedDictMeta, name, (dict,), ns)
+
+ annotations = {}
+ own_annotations = ns.get('__annotations__', {})
+ own_annotation_keys = set(own_annotations.keys())
+ msg = "TypedDict('Name', {f0: t0, f1: t1, ...}); each t must be a type"
+ own_annotations = {
+ n: _type_check(tp, msg, module=tp_dict.__module__)
+ for n, tp in own_annotations.items()
+ }
+ required_keys = set()
+ optional_keys = set()
+
+ for base in bases:
+ annotations.update(base.__dict__.get('__annotations__', {}))
+ required_keys.update(base.__dict__.get('__required_keys__', ()))
+ optional_keys.update(base.__dict__.get('__optional_keys__', ()))
+
+ annotations.update(own_annotations)
+ if total:
+ required_keys.update(own_annotation_keys)
+ else:
+ optional_keys.update(own_annotation_keys)
+
+ tp_dict.__annotations__ = annotations
+ tp_dict.__required_keys__ = frozenset(required_keys)
+ tp_dict.__optional_keys__ = frozenset(optional_keys)
+ if not hasattr(tp_dict, '__total__'):
+ tp_dict.__total__ = total
+ return tp_dict
+
+ __call__ = dict # static method
+
+ def __subclasscheck__(cls, other):
+ # Typed dicts are only for static structural subtyping.
+ raise TypeError('TypedDict does not support instance and class checks')
+
+ __instancecheck__ = __subclasscheck__
+
+
+def TypedDict(typename, fields=None, /, *, total=True, **kwargs):
+ """A simple typed namespace. At runtime it is equivalent to a plain dict.
+
+ TypedDict creates a dictionary type that expects all of its
+ instances to have a certain set of keys, where each key is
+ associated with a value of a consistent type. This expectation
+ is not checked at runtime but is only enforced by type checkers.
+ Usage::
+
+ class Point2D(TypedDict):
+ x: int
+ y: int
+ label: str
+
+ a: Point2D = {'x': 1, 'y': 2, 'label': 'good'} # OK
+ b: Point2D = {'z': 3, 'label': 'bad'} # Fails type check
+
+ assert Point2D(x=1, y=2, label='first') == dict(x=1, y=2, label='first')
+
+ The type info can be accessed via the Point2D.__annotations__ dict, and
+ the Point2D.__required_keys__ and Point2D.__optional_keys__ frozensets.
+ TypedDict supports two additional equivalent forms::
+
+ Point2D = TypedDict('Point2D', x=int, y=int, label=str)
+ Point2D = TypedDict('Point2D', {'x': int, 'y': int, 'label': str})
+
+ By default, all keys must be present in a TypedDict. It is possible
+ to override this by specifying totality.
+ Usage::
+
+ class point2D(TypedDict, total=False):
+ x: int
+ y: int
+
+ This means that a point2D TypedDict can have any of the keys omitted.A type
+ checker is only expected to support a literal False or True as the value of
+ the total argument. True is the default, and makes all items defined in the
+ class body be required.
+
+ The class syntax is only supported in Python 3.6+, while two other
+ syntax forms work for Python 2.7 and 3.2+
+ """
+ if fields is None:
+ fields = kwargs
+ elif kwargs:
+ raise TypeError("TypedDict takes either a dict or keyword arguments,"
+ " but not both")
+
+ ns = {'__annotations__': dict(fields)}
+ try:
+ # Setting correct module is necessary to make typed dict classes pickleable.
+ ns['__module__'] = sys._getframe(1).f_globals.get('__name__', '__main__')
+ except (AttributeError, ValueError):
+ pass
+
+ return _TypedDictMeta(typename, (), ns, total=total)
+
+_TypedDict = type.__new__(_TypedDictMeta, 'TypedDict', (), {})
+TypedDict.__mro_entries__ = lambda bases: (_TypedDict,)
+
+
+class NewType:
+ """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 callable 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 __init__(self, name, tp):
+ self.__qualname__ = name
+ if '.' in name:
+ name = name.rpartition('.')[-1]
+ self.__name__ = name
+ self.__supertype__ = tp
+ def_mod = _caller()
+ if def_mod != 'typing':
+ self.__module__ = def_mod
+
+ def __repr__(self):
+ return f'{self.__module__}.{self.__qualname__}'
+
+ def __call__(self, x):
+ return x
+
+ def __reduce__(self):
+ return self.__qualname__
+
+ def __or__(self, other):
+ return Union[self, other]
+
+ def __ror__(self, other):
+ return Union[other, self]
+
+
+# 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__ = ()
+
+ @property
+ @abstractmethod
+ def mode(self) -> str:
+ pass
+
+ @property
+ @abstractmethod
+ def name(self) -> str:
+ pass
+
+ @abstractmethod
+ def close(self) -> None:
+ pass
+
+ @property
+ @abstractmethod
+ 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__ = ()
+
+ @property
+ @abstractmethod
+ def buffer(self) -> BinaryIO:
+ pass
+
+ @property
+ @abstractmethod
+ def encoding(self) -> str:
+ pass
+
+ @property
+ @abstractmethod
+ def errors(self) -> Optional[str]:
+ pass
+
+ @property
+ @abstractmethod
+ def line_buffering(self) -> bool:
+ pass
+
+ @property
+ @abstractmethod
+ 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, 1)
+Match = _alias(stdlib_re.Match, 1)
+
+class re:
+ """Wrapper namespace for re type aliases."""
+
+ __all__ = ['Pattern', 'Match']
+ Pattern = Pattern
+ Match = Match
+
+
+re.__name__ = __name__ + '.re'
+sys.modules[re.__name__] = re
+
+
+