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 get(self, key, default=None):
        try:
            value = self[key]
        except KeyError:
            value = self._to_python(default)
        return value