60     def _remove_item(self, item_id):  argument
61         nonexpired_pairs = [pair for pair in self._item_time_pairs() if pair[0] != item_id]
73     def _expire_item(key, item_id):  argument
75         active_work_items._remove_item(item_id)
78     def expire_item(self, item_id):  argument
79         return db.run_in_transaction(self._expire_item, self.key(), item_id)
87         for item_id in work_item_ids:
88             if item_id not in self.item_ids:
89                 self._append_item_time_pair([item_id, time.mktime(now.timetuple())])
90                 return item_id
93     def time_for_item(self, item_id):  argument
95             if active_item_id == item_id: