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?
PS 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!"

Answer 2

Is this what You were going for:

class A:
    def __init__(self):
        pass

    @classmethod
    def foo(cls):
        return "Hello!"

    def bar(self):
        return "Hello again!"


print(A.foo())
print(A().bar())

Answer 3

read docs here

class MyClass:
    def method(self):
        # instance Method
        return 'instance method called', self

    @classmethod
    def cls_method(cls):
        #Classmethod
        return 'class method called', cls

    @staticmethod
    def static_method():
        # static method
        return 'static method called'

You need to instantiate MyClass To reach(Call) Instance Method

test = MyClass()
test.method()

You Can directly access class Method without instantiate

MyClass.cls_method()
MyClass.static_method()