code: def close(self):
          
          if not self.closed and not self.closing:
              logger.debug(
                  "%s[%s] closing...",
                  self.__class__.__name__,
                  id(self),
              )
              self._closing.set()
              future = asyncio.ensure_future(self.on_close(), loop=self.loop)
              future.add_done_callback(self._set_closed)
docs: Close the instance.