new_contents: # -*- coding: utf-8 -*-
  
  import asyncio
  
  from sanic import Sanic
  
  app = Sanic()
  
  
  async def notify_server_started_after_five_seconds():
      await asyncio.sleep(5)
      print('Server successfully started!')
  
  app.add_task(notify_server_started_after_five_seconds())
  
  if __name__ == "__main__":
      app.run(host="0.0.0.0", port=8000)
  
subject: add `add_task_sanic.py`