Error-- server.serve_forever()

[jamwu]

Exception in thread ftp:
Traceback (most recent call last):
  File "D:\Python34\lib\threading.py", line 921, in _bootstrap_inner
    self.run()
  File "D:\Python34\lib\threading.py", line 869, in run
    self._target(*self._args, **self._kwargs)
  File "E:\#Magic_Project#\magic\ftpServer.py", line 84, in start
    self.server.serve_forever()
  File "D:\Python34\lib\site-packages\pyftpdlib\servers.py", line 213, in serve_forever
    self.ioloop.loop(timeout, blocking)
  File "D:\Python34\lib\site-packages\pyftpdlib\ioloop.py", line 348, in loop
    poll(soonest_timeout)
  File "D:\Python34\lib\site-packages\pyftpdlib\ioloop.py", line 446, in poll
    r, w, e = select.select(self._r, self._w, [], timeout)
OSError:  [WinError 10038] an operation was attempted on something that is not a socket

I used python3 and can run the script.Connect the ftp server with filezilla on win10.When after some action(refresh,create file,write file,del file and so on) on filezilla,will get this error.anyone have an idear for this?