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 _scale_vars(s, v_list):
  """Scale all variables in v_list by s."""
  return [s * v for v in v_list]