As of March 15th, 2014, there is no license file in the repository of 'pyst'.

However, in the project page (http://sourceforge.net/projects/pyst/) it
says its license is the "License GNU Library or Lesser General Public License
version 2.0 (LGPLv2)".
In the file 'setup.py' it says the licenses are:

* Python Software Foundation License
* GNU Library or Lesser General Public License (LGPL)

For more information about the LGPL, see:

* https://www.gnu.org/licenses/lgpl-2.0.txt
* https://www.gnu.org/copyleft/lesser.html
