code: async def shutdown(self):
          
          logger.display("Looper shutting down now...", extra={"cli": False})
          self.running = False
          start = time.perf_counter()
          if not self.runFut.done():
              await self.runFut
          self.stopall()
          logger.display("Looper shut down in {:.3f} seconds.".
                         format(time.perf_counter() - start), extra={"cli": False})
          # Unset signal handlers, bug: https://bugs.python.org/issue23548
          for sig_name in self.signals:
              logger.debug("Unsetting handler for {}".format(sig_name))
              sig_num = getattr(signal, sig_name)
              self.loop.remove_signal_handler(sig_num)
docs: Shut down this Looper.