Function TypeAlias

Lib/typing.py:785–798

Special form for marking type aliases. Use TypeAlias to indicate 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 examp

(self, parameters)

@_SpecialForm
def TypeAlias(self, parameters):
    """Special form for marking type aliases.

    Use TypeAlias to indicate 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