Advanced Python 3 Programming Techniques

Chapter 13. Abstract Base Classes

An abstract base class (ABC) is a class that cannot be used to create objects. Instead, the purpose of such classes is to define interfaces, that is, to in effect list the methods and properties that classes that inherit the abstract base class must provide. This is useful because we can use an abstract base class as a kind of promise—a promise that any derived class will provide the methods and properties that the abstract base class specifies.^[*]

^[*] Python’s abstract base classes are described in PEP 3119 (www.python.org/dev/peps/pep-3119), which also includes a very useful rationale and is well worth reading.

Abstract base classes are classes that have at least one abstract method or property. ...