This is PADS, a library of Python Algorithms and Data Structures implemented by David Eppstein of the University of California, Irvine.
The current version of PADS may be found at http://www.ics.uci.edu/~eppstein/PADS/, as individual files or as a git repository that may be copied by the command line
git clone http://www.ics.uci.edu/~eppstein/PADS/.git
PADS is licensed under the MIT Licence (http://opensource.org/licenses/MIT). For more information, see the file LICENSE.
Copyright (c) 2002-2015, David Eppstein