def _add_to_queue_(self, lst): try: self._lock.acquire() obj_set, obj_event = self._get_conflicted_list_(lst) if obj_event: return obj_event event = Event() event.clear() obj_set = set(lst) event.transaction_id = self._get_root_transaction_id_() self._active_lists[id(lst)] = obj_set, event return None finally: self._lock.release()