code: def install_signal_handlers(self):
          
  
          self.graceful_stop = False
  
          def request_shutdown_now():
              self.shutdown_now()
  
          def request_shutdown_graceful():
  
              # Second time CTRL-C, shutdown now
              if self.graceful_stop:
                  self.shutdown_now()
              else:
                  self.graceful_stop = True
                  self.shutdown_graceful()
  
          # First time CTRL-C, try to shutdown gracefully
          gevent.signal(signal.SIGINT, request_shutdown_graceful)
  
          # User (or Heroku) requests a stop now, just mark tasks as interrupted.
          gevent.signal(signal.SIGTERM, request_shutdown_now)
docs: Handle events like Ctrl-C from the command line.