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

a_copy_sig.py

# this needs only a single line, besides imports! only tested with pyright/pylance.
# downside: no functools.wraps, at runtime __doc__ etc. will be wrong
from functools import partial, wraps
from typing import cast

# just copy this and replace "otherfunc" with the function you want to copy from
@partial(cast, type(otherfunc))
def myfunc(*args, **kwargs):
    return otherfunc(*args, **kwargs)


# a version with functools.wraps, probably not worth it
# use the proper function from below instead
@partial(partial(cast, type(otherfunc)), wraps(otherfunc))
def myfunc(*args, **kwargs):
    return otherfunc(*args, **kwargs)


# just for fun, a version where you don't have to paste otherfunc twice. definitely NOT worth it
@(lambda src: partial(partial(cast, type(src)), wraps(src)))(otherfunc)
def myfunc(*args, **kwargs):
    return otherfunc(*args, **kwargs)

# License: MIT

b_copy_sig_wraps.py

from functools import partial, wraps
from typing import Callable, ParamSpec, TypeVar, cast

P = ParamSpec("P")
R = TypeVar("R")


def copy_sig(s: Callable[P, R]) -> Callable[[Callable[..., R]], Callable[P, R]]:
    """Decorator to copy the function signature from another function.
    Especially useful when overwriting methods with many arguments
    Note: 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[..., R]) -> Callable[P, R]:
        return cast(Callable[P, R], wraps(s)(func))

    return return_func