old_contents: from tornado import web as tw
  
  from .templates import index_html
  
  
  class IndexHandler(tw.RequestHandler):
  
      def get(self):
          self.render(index_html)
  
new_contents: from aiohttp import web as aw
  import aiohttp_jinja2 as aj
  
  
  class IndexHandler(aw.View):
  
      async def get(self):
          return aj.render_template('index.html', self.request, None)
  
subject: rewrite view