我正在嘗試從 SFTP 服務器下載一些文件。我使用這個代碼：keydata = b"""AAAAB3Nza.............CNpvoUP7p"""key = paramiko.RSAKey(data=decodebytes(keydata))cnopts = pysftp.CnOpts()cnopts.hostkeys.add(host, 'ssh-rsa', key)host = 'sftp.foo.com'username = 'test'password = 'test'with pysftp.Connection(host=host, username=username, password=password, cnopts=cnopts) as sftp:    sftp.listdir()    .....但我收到以下錯誤：Exception raised:    Traceback (most recent call last):      File "/home/myuser/src/ftp-data/ftp_data/downloader_v2.py", line 25, in main        sftp.listdir()      File "/home/myuser/environments/python3.5.2_ubuntu16.04/lib/python3.5/site-packages/pysftp/__init__.py", line 591, in listdir        self._sftp_connect()      File "/home/myuser/environments/python3.5.2_ubuntu16.04/lib/python3.5/site-packages/pysftp/__init__.py", line 205, in _sftp_connect        self._sftp = paramiko.SFTPClient.from_transport(self._transport)      File "/home/myuser/environments/python3.5.2_ubuntu16.04/lib/python3.5/site-packages/paramiko/sftp_client.py", line 165, in from_transport        window_size=window_size, max_packet_size=max_packet_size      File "/home/myuser/environments/python3.5.2_ubuntu16.04/lib/python3.5/site-packages/paramiko/transport.py", line 879, in open_session        timeout=timeout,      File "/home/myuser/environments/python3.5.2_ubuntu16.04/lib/python3.5/site-packages/paramiko/transport.py", line 1006, in open_channel        raise e      File "/home/myuser/environments/python3.5.2_ubuntu16.04/lib/python3.5/site-packages/paramiko/transport.py", line 2055, in run        ptype, m = self.packetizer.read_message()      File "/home/myuser/environments/python3.5.2_ubuntu16.04/lib/python3.5/site-packages/paramiko/packet.py", line 459, in read_message        header = self.read_all(self.__block_size_in, check_rekey=True)        raise EOFError()    EOFError相同的代碼可以在我嘗試過的其他 SFTP 主機上正常運行。我還可以使用命令行（Ubuntu）正確下載文件sftp。listdir()如果我替換為pwd()or cd().... ，我會得到同樣的錯誤。我使用以下版本：paramiko==2.7.2 和 pysftp==0.2.9我在這里缺少什么？