How to inherit a method attribute [python]

I am trying to pass some attributes from a method in a parent class to a method in a child class. And after that I wish to use a decorator that uses that attribute.

Suppose I have two classes and a decorator like these:

def my_decorator(fun):
    inner(*args, **kwargs):
        if fun.some_attr == 'value':
            out = fun(*args, **kwargs)
        else:
            out = None
        return out
     return inner

class A:
    def some_method_in_A(self):
        return 1
    some_method_in_A.some_attr = 'value'

class B(A):
    @my_decorator
    def some_method_in_B(self):
        super(B, self).some_method_in_A()

What I want is to have some_attr set to 'value' in some_method_in_B. This attribute has to be available for my_decorator. Is it possible to do it?

This is something that I would have to do for lots of methods in class B so it would be nice to do it in a compact way.