code: async def set_headline(self, name, level, message):
          
  
          if name not in self.services:
              raise ArgumentError("Unknown service name", short_name=name)
  
          self.services[name]['state'].set_headline(level, message)
  
          headline = self.services[name]['state'].headline.to_dict()
          await self._notify_update(name, 'new_headline', headline)
docs: Set the sticky headline for a service.
  
          Args:
              name (string): The short name of the service to query
              level (int): The level of the message (info, warning, error)
              message (string): The message contents