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

        prio_set_list.add(0, obj)
        assert obj in prio_set_list
def _update_width(self, width_diff):
    if self._items_total_width is None:
      self._items_total_width = self.get_allocation().width