code: def _subthread_handle_readable(self, conn):
          
  
          if self.handle_readable(conn):
              self.register(conn)
          else:
              self.disconnect(conn)
docs: Handles readable client sockets. Calls the user modified handle_readable with
          the client socket as the only variable. If the handle_readable function returns
          true the client is again registered to the selector object otherwise the client
          is disconnected.