v0.0.6
PEP-483 says that Callable is covariant in the return type https://peps.python.org/pep-0483/#covariance-and-contravariance so `Callable[P, R]` and `Callable[P, Awaitable[R]]` are both already "in" `Callable[P, Union[R, Awaitable[R]]]`.
PEP-483 says that Callable is covariant in the return type https://peps.python.org/pep-0483/#covariance-and-contravariance so `Callable[P, R]` and `Callable[P, Awaitable[R]]` are both already "in" `Callable[P, Union[R, Awaitable[R]]]`.