Copy a functions/methods signature for typing without specifying each individual argument type

gistfile1.txt

from typing import Callable, ParamSpec, TypeVar, cast


P = ParamSpec("P")
T = TypeVar("T")


def copy_sig(source_func: Callable[P, T]) -> Callable[[Callable[..., T]], Callable[P, T]]:
    """Decorator to copy the function signature from source_func
    Especially useful when overwriting methods with many arguments
    CAREFUL: Only works towards the outside. Inside the function the types won't show up.
    
    @copy_sig(source_func)
    def other_func(*args, **kwargs):
        ...
    """
    def return_func(func: Callable[..., T]) -> Callable[P, T]:
        return cast(Callable[P, T], func)
    return return_func