parameters: (self, state: State)
return_statement: return TransitionCallbackReturn.SUCCESS
docstring: Shutdown the node, after a shutting-down transition is requested.
  
      on_shutdown callback is being called when the lifecycle node
      enters the "shutting down" state.
      
      :return: The state machine either invokes a transition to the "finalized" state or stays
      in the current state depending on the return value.
        TransitionCallbackReturn.SUCCESS transitions to "unconfigured".
        TransitionCallbackReturn.FAILURE transitions to "inactive".
        TransitionCallbackReturn.ERROR or any uncaught exceptions to "errorprocessing"
docstring_summary: Shutdown the node, after a shutting-down transition is requested.
docstring_tokens: Shutdown the node after a shutting - down transition is requested .
function: def on_shutdown(self, state: State) -> TransitionCallbackReturn:
      """
      Shutdown the node, after a shutting-down transition is requested.
  
      on_shutdown callback is being called when the lifecycle node
      enters the "shutting down" state.
      
      :return: The state machine either invokes a transition to the "finalized" state or stays
      in the current state depending on the return value.
        TransitionCallbackReturn.SUCCESS transitions to "unconfigured".
        TransitionCallbackReturn.FAILURE transitions to "inactive".
        TransitionCallbackReturn.ERROR or any uncaught exceptions to "errorprocessing"
      """
      self.destroy_timer(self._timer)
      self.destroy_publisher(self._pub)
  
      self.get_logger().info('on_shutdown() is called.')
      return TransitionCallbackReturn.SUCCESS
function_tokens: def on_shutdown ( self , state : State ) -> TransitionCallbackReturn : self . destroy_timer ( self . _timer ) self . destroy_publisher ( self . _pub ) self . get_logger ( ) . info ( 'on_shutdown() is called.' ) return TransitionCallbackReturn . SUCCESS