A skip list container class in Python

We'll start with a rudimentary documentation string for the module, pointing back to the online documentation:

"""pyskip.py:  A container class for ordered sets in Python.

    $Revision: 1.22 $  $Date: 2008/01/09 05:38:30 $

For documentation, see:
    http://www.nmt.edu/tcc/help/lang/python/examples/pyskip/    
"""

Next we'll need to import one of the Python standard modules, the random number generator:

import random