code: def do_mute(self, sender, body, args):
          
          if sender.get('MUTED'):
              self.send_message('you are already muted', sender)
          else:
              self.broadcast('%s has muted this chatroom' % (sender['NICK'],))
              sender['QUEUED_MESSAGES'] = []
              sender['MUTED'] = True
docs: Temporarily mutes chatroom for a user