'Send a QUIT command to disconnect from the server.
@rtype: L{Deferred <defer.Deferred>} which successfully fires with
L{bytes} or fails with L{ServerErrorResponse}
@return: A deferred which fires when the server response is received.
On an OK response, the deferred succeeds with the server
response minus the status indicator.  On an ERR response, the
deferred fails with a server error response failure.'

def quit(self):

    return self.sendShort('QUIT', None)
