Python explicit inheritance

inheritance.py

2
>>> 
| vim a.py

class X:
    def __init__(self, a,b,c):
        self.a, self.b, self.c = a,b,c

    def get_a(self):
        return self.a
   
    def set_a(self, a):
        self.a = a


class Y:
    def __init__(self):
        self.x = X(1, 2, 3)

    def get_a(self):
        return 10000

    def __dir__(self):
        return ['a', 'b']

    # only calls this if the attrib has not been defined
    def __getattr__(self, attr):
        return getattr(self.x, attr)