We currently still use Python 2 for our production sites, but Lino is mostly ported to Python 3. Basic instructions for working on this ticket:

• Check [url travis-ci.org/lsaffre/lino] in order to monitor what needs to be done.
• Get a clone of the Lino repository.
• Create two virtualenvs, one with Python 2 and the other with Python 3
• Install the clone (using "pip install -e") into both environments and run the test suite under both environmens.
• Try to make changes so that the test suite passes in both environments.