code: def command(self, payload):
          
          data = self.message(MessageType.COMMAND, payload)
          if data:
              return json.loads(data, object_hook=CommandReply)
          else:
              return None
docs: Send a command to i3. See the `list of commands
          <http://i3wm.org/docs/userguide.html#_list_of_commands>`_ in the user
          guide for available commands. Pass the text of the command to execute
          as the first arguments. This is essentially the same as using
          ``i3-msg`` or an ``exec`` block in your i3 config to control the
          window manager.
  
          :rtype: List of :class:`CommandReply` or None if the command causes i3
          to restart or exit and does not give a reply.