from typing import Optional, TypeVar, Type

_T = TypeVar('_T')

class Managed:
    @classmethod
    def current(cls: Type[_T], value: Optional[_T] = None, required: bool = True) -> _T: ...

    def __call__(self, func: _T) -> _T: ...

    def __enter__(self: _T) -> _T: ...

class DefaultManaged(Managed): ...