code: def print_port(self, stream=sys.stdout):
          
          stream.write(str(self.server_address[1]))
          stream.write("\n")
          stream.flush()
docs: Print port this EPC server runs on.
  
          As Emacs client reads port number from STDOUT, you need to
          call this just before calling :meth:`serve_forever`.
  
          :type stream: text stream
          :arg  stream: A stream object to write port on.
                        Default is :data:`sys.stdout`.