我在我的 Django 项目中使用了 mongoDB 的 Motor 驱动程序，但在将我的数据（作为游标来自数据库的数据）转换为列表时遇到问题，这是我的代码：
documents = db.factor.aggregate([{"$limit": 3},
{"$lookup": {"from": "subfactor", "localField": "_id", "foreignField": "factor_id", "as": "subfactor"}}])
for d in await list(documents):
print(d)
和错误：
File "/usr/lib/python3.8/asyncio/runners.py", line 43, in run
return loop.run_until_complete(main)
File "/usr/lib/python3.8/asyncio/base_events.py", line 595, in run_until_complete
self.run_forever()
File "/usr/lib/python3.8/asyncio/base_events.py", line 563, in run_forever
self._run_once()
File "/usr/lib/python3.8/asyncio/base_events.py", line 1808, in _run_once
event_list = self._selector.select(timeout)
File "/usr/lib/python3.8/selectors.py", line 468, in select
fd_event_list = self._selector.poll(timeout, max_ev)