% python setup.py install
# or copy pyderasn.py (+six.py) to your PYTHONPATH
-PyDERASN depends on `six <https://pypi.python.org/pypi/six>`__ package
+PyDERASN depends on `six <https://pypi.org/project/six/>`__ package
for keeping compatibility with Py27/Py35. It is included in the tarball.
You can also find it mirrored on :ref:`download <download>` page.