def test_contains(self):
        prio_set_list = event._PrioritizedSetList()
        obj = object()

        prio_set_list.add(0, obj)
        assert obj in prio_set_list
def add_item(self, item_value=None, index=None):
    if item_value is None:
      item_value = self._new_item_default_value