code: def onboarding_message(**payload):
      
      # Get WebClient so you can communicate back to Slack.
      web_client = payload["web_client"]
  
      # Get the id of the Slack user associated with the incoming event
      user_id = payload["data"]["user"]["id"]
  
      # Open a DM with the new user.
      response = web_client.im_open(user_id)
      channel = response["channel"]["id"]
  
      # Post the onboarding message.
      start_onboarding(web_client, user_id, channel)
docs: Create and send an onboarding welcome message to new users. Save the
      time stamp of this message so we can update this message in the future.