new_contents: # -*- coding: utf-8 -*-
  
  import logging
  import tornado.web
  
  logger = logging.getLogger(__name__)
  
  
  class MainHandler(tornado.web.RequestHandler):
      """Handle '/' endpoint (root server endpoint).
      """
  
      def get(self):
          """Handle GET requests. Serve the index web page.
          """
          logger.debug('render index.html file')
          self.render('index.html')
          return
  
subject: Create MainHandler.py