ResourceWarning: unclosed socket.socket fd=708, family=Addr

跑测试用例时发现的，用例正常执行成功，提示：

C:\Python37\lib\email\feedparser.py:89: ResourceWarning: unclosed 
  for ateof in reversed(self._eofstack):
ResourceWarning: Enable tracemalloc to get the object allocation traceback

问题不大，解决如下