I forked this kind of jankily because I had some issues using this
for a project I was working on, and rather than find a different 
library I thought I fix this one.

I downloaded the source from https://pypi.python.org/pypi/DecisionTree/2.2.1

The original README follows

------------------------------------------------------------------------

The DecisionTree module is a Python implementation for
constructing a decision tree from multidimensional training
data and for using the decision tree thus constructed for
classifying new data.

It is highly recommended that you read the README in the 
'Examples' directory if you wish to become familiar with
this module.

If there are any questions about this module, contact the
author at '[email protected]' with the string DecisionTree in
the subject line to get past his spam filter.