# Topic covered
* Classes, Objects
* Inheritance, Polymorphism

It’s important to know how each of the paradigms work and how they urge you to structure the code within them, but with respect to architecture, Object-Oriented Programming is the clear tool for the job.

Not only does Object-Oriented programming enable us to create a plugin architecture and build flexibility into our projects; OOP comes with the 4 principles of OOP (encapsulation, inheritance, polymorphism, and abstraction) that help us create rich domain models.

SNC: Python OOPs

3.1 Classes and Objects

• Noun –> Classes (Objects)
• Verb –> Behaviour

Classes

2 kind of relationships among classes

• has a relation
  • Composition
    • Customer has-a Credit card
    • No existence of card without customer
  • Aggregation
    • Cart has-a Product
    • Product can exist without cart
• is a relation
  • It an inheritance relation
  • ParkingLesson is a CarLesson
  • DrivingLesson is a CarLesson

Inheritance and Polymorphism