Try to deal with this warning/error: DeprecationWarning: generator 'iter_roles' raised StopIteration PEP479 specifies how to rework it by using return rather than raise StopIteration. I am not sure if this is right, but test/test_cgi.py::FormTestCase::testRoles is still passing.

try:
    # Python 2.
    my_input = raw_input
except NameError:
    # Python 3+.
    my_input = input