redis-py - redis-py は AttributeError を発生させます

Question

どのような状況redis-pyで次のAttributeError例外が発生しますか? ベースの例外のみを発生させるように設計されて
いませんか? 合理的な処理ロジックは何でしょうか?redis-pyredis.exceptions.RedisError

Traceback (most recent call last):
  File "c:\Python27\Lib\threading.py", line 551, in __bootstrap_inner
    self.run()
  File "c:\Python27\Lib\threading.py", line 504, in run
    self.__target(*self.__args, **self.__kwargs)
  File C:\Users\Administrator\Documents\my_proj\my_module.py", line 33, in inner
    ret = protected_func(*args, **kwargs)
  File C:\Users\Administrator\Documents\my_proj\my_module.py", line 104, in _listen
    for message in _pubsub.listen():
  File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\client.py", line 1555, in listen
    r = self.parse_response()
  File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\client.py", line 1499, in parse_response
    response = self.connection.read_response()
  File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\connection.py", line 306, in read_response
    response = self._parser.read_response()
  File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\connection.py", line 104, in read_response
    response = self.read()
  File "C:\Users\Administrator\virtual_environments\my_env\lib\site-packages\redis\connection.py", line 89, in read
    return self._fp.readline()[:-2]
AttributeError: 'NoneType' object has no attribute 'readline'