Inheritance

Python supports single inheritance with optional multiple inheritance—use sparingly. Subclasses override methods; call super with super() to extend parent behavior—like Java super or C# base.

Subclass example

class Animal:
    def speak(self):
        return "..."

class Dog(Animal):
    def speak(self):
        return "woof"

class ServiceDog(Dog):
    def speak(self):
        base = super().speak()
        return f"{base} (trained)"

Method Resolution Order (MRO)

Python uses C3 linearization for MRO—ClassName.__mro__ shows lookup order in multiple inheritance. Prefer composition over deep inheritance trees.

Important interview questions and answers

1. Q: super() purpose?
   A: Delegates to the next class in MRO—works with multiple inheritance unlike hard-coded parent names.
2. Q: Composition vs inheritance?
   A: Favor has-a relationships when behavior can be shared without is-a taxonomies—especially in Django models later.

Self-check

1. How call a parent method from a subclass?
2. What does MRO stand for?

Pitfall: Deep inheritance hierarchies hurt maintenance—prefer composition for shared behavior.