gistfile1.py

import inspect


def inherit(*, base, docs=False, signature=False):
    assert docs or signature
    assert isinstance(base, type) # we can also support functions

    def wrap(func):
        base_func = getattr(base, func.__name__)

        if docs:
            doc = getattr(base_func, '__doc__', None)
            assert doc
            func.__doc__ = doc

        if signature:
            func.__signature__ = inspect.signature(base_func)

        return func

    return wrap


if __name__ == '__main__':
    class A:
        def foo(self, a):
            'aaa'
            return a


    class B(A):
        @inherit(base=A, docs=True, signature=True)
        def foo(self, *args, **kwargs):
            return super().foo(*args, **kwargs) + 32


    assert B().foo.__doc__ == 'aaa'
    assert str(inspect.signature(B().foo)) == '(a)'
    assert str(inspect.signature(B.foo)) == '(self, a)'

    print('ok')