class Meta(type):
    def __getattribute__(self, name):
        d = type.__getattribute__(self, "__dict__")
        if name not in d:
            raise AttributeError
        else:
            return d[name]

class A(metaclass=Meta):
    x = 1

class B(A):
    y = 2

print(B.y) #2
print(B().y) #2
print(B().x) #1
print(B.x) #AttributeError