Track 11 · Lesson 12 of 12

Designing with classes: inventory mini project

Decide which classes a program needs and what each is responsible for, define shared interfaces with abstract base classes, and build an inventory and ordering system in milestones.

You will be able to

• Split a problem into small classes, each with one clear responsibility
• Choose between inheritance, composition and plain data classes for each part of a design
• Define an interface with abc.ABC and @abstractmethod, and implement it in subclasses
• Build a multi-class inventory and ordering system step by step, keeping every object's data valid