The PySNMP software is provided under terms and conditions of BSD-style license, and can be freely downloaded from PyPI package.
Besides official releases, if you want to try the cutting-edge development code then it could be taken from PySNMP GitHub repository. It may be less stable in regards to general operation and changes to public interfaces, but it’s first to contain fixes to recently discovered bugs.
The best way to obtain PySNMP and dependencies is to run:
$ pip install pysnmp-lextudio
In case of any issues, please open a new GitHub issue so we could try to help out.