oop_python1-5 - basic
oop_python6-10 - inheritance
oop_python11-15 - Multiple inheritance, diamond inheritance, class methods, static method, abstract class
oop_python16-20.py - Inhertance methods, Composition, CORE Syntax Resolution, Inheriting from builtins classes, @Property decorator
oop_python21-25.py - With context, new style classes, exception handling, Serialization
oop_python26-30.py - pdb, logging, timing