Python: How can i decorate function to change it into class method

Question

I have code like this and i want to write decorator which will add decoradted function as class method of class A.

class A:
    pass

@add_class_method(A)
def foo():
    return "Hello!"

@add_instance_method(A)
def bar():
    return "Hello again!"

assert A.foo() == "Hello!"
assert A().bar() == "Hello again!"

Answer 1

What about this approach?
P.S. The code is not structurally optimized for the sake of clarity

from functools import wraps


class A:
    pass


def add_class_method(cls):
    def decorator(f):
        @wraps(f)
        def inner(_, *args, **kwargs):
            return f(*args, **kwargs)

        setattr(cls, inner.__name__, classmethod(inner))

        return f

    return decorator


def add_instance_method(cls):
    def decorator(f):
        @wraps(f)
        def inner(_, *args, **kwargs):
            return f(*args, **kwargs)

        setattr(cls, inner.__name__, inner)

        return f

    return decorator


@add_class_method(A)
def foo():
    return "Hello!"


@add_instance_method(A)
def bar():
    return "Hello again!"


assert A.foo() == "Hello!"
assert A().bar() == "Hello again!"