Python-cluster is a simple package that allows to create several 
groups (clusters) of objects from a list. It's meant to be flexible 
and able to cluster any object. To ensure this kind of flexibility, 
you need not only to supply the list of objects, but also a function 
that calculates the similarity between two of those objects. 
For simple datatypes, like integers, this can be as simple as a 
subtraction, but more complex calculations are possible. 

WWW: https://pypi.python.org/pypi/cluster