container objects

Containers are objects that hold other objects (sometimes I called them meta-objects, since one hardly uses them directly) get all of the methods of standard objects, plus 2 to 4 additional methods:

• the index operator[],
• or containment test (in)

The getstate method returns the size of the container or the number of other elements within it.

This is a preliminary exploration. It may be that more methods will be necessary, like size or a test for non-zero, yet I believe these can be accommodated with get_state.... STUB

A built-in Stack object exists in the shell offering a First-In, Last-Out container. The shell stack can be accessed with what operator, symbol, or name?

The Stack(Container) adds push, pop