Abstract Base Classes and Type Hints

Overview

The concept of an abstract base class is closely tied to the idea of a generic class. An abstract base class is often generic concerning some detail supplied by a concrete implementation.

Most of Python’s generic classes – classes like list, dict, and set – can be used as type hints, which can be parameterized to narrow the domain. There’s a world of difference between list[Any] and list[int]; the value $["a", 42, 3.14]$ ...