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 __init__(self, key, child_proxy):
        try:
            self._key = int(key)
        except ValueError:
            self._key = key
        self._child_proxy = child_proxy