This example shows how an abstract base class from the Python standard library can be used as the basis for a custom dictionary type, one where the entries expire after a given length of time, and ...

This might sound a bit abstract, but it’s a powerful concept that allows you to customize class creation in Python. In Python, everything is an object, including classes.

Abstract classes and interfaces in Java serve fundamentally different purposes. Learn the differences between these Java language elements and how to use them in your programs.