code: def _shutdown(self, message=None, code=0):
          
          if self._shutdown_complete:
              # Make sure we don't accidentally re-run the all cleanup
              sys.exit(code)
  
          if self.shutdown_callback is not None:
              # Call the shutdown callback with a message suitable for
              # logging and the exit code
              self.shutdown_callback(message, code)
  
          if self.pidfile is not None:
              self._close_pidfile()
  
          self._shutdown_complete = True
          sys.exit(code)
docs: Shutdown and cleanup everything.