Python 3 Object-Oriented Programming - Third Edition

The diamond problem

We can use multiple inheritance to add this new class as a parent of our existing Friend class. The tricky part is that we now have two parent __init__ methods, both of which need to be initialized. And they need to be initialized with different arguments. How do we do this? Well, we could start with a naive approach:

class Friend(Contact, AddressHolder): 
    def __init__( 
        self, name, email, phone, street, city, state, code): 
        Contact.__init__(self, name, email) 
        AddressHolder.__init__(self, street, city, state, code) 
        self.phone = phone 

In this example, we directly call the __init__ function on each of the superclasses and explicitly pass the self argument. This example technically works; we can access the different variables ...