This module defines a class that acts as a wrapper around list objects. It is a useful base class for your own list-like classes, which can inherit from them and override existing methods or add new ones. In this way one can add new behaviours to lists.
The UserList module defines the UserList class:
. list can be either a regular Python list, or an instance of UserList (or a subclass).
In addition to supporting the methods and operations of mutable sequences (see section 2.1.5), UserList instances provide the following attribute: