So far, we’ve used functions to organise code. Object-oriented programming (OOP) is a second way: we bundle related data and behaviour together into classes, then create objects from those classes.

Python is an OOP language at heart — every value you’ve ever used (a list, a string, a number) is an object. This section teaches you how to build your own.

What’s in this section

1. Classes and objects — defining a class, creating instances
2. Constructors and instance attributes — __init__ and self
3. Methods — functions that belong to a class
4. Properties — controlled access to attributes
5. Inheritance — building new classes on top of existing ones
6. Data classes — classes with no boilerplate

We’ll keep the OOP simple here. The next section covers strict typing and Protocol, which is where modern Python’s type system really shines.