def test_bool(self):
        prio_set_list = event._PrioritizedSetList()

        assert bool(prio_set_list) is False

        prio_set_list.add(0, None)
        assert bool(prio_set_list) is True
def poll(cls, context):
        userpref = context.user_preferences
        return (userpref.active_section == 'SYSTEM')