old_contents: import tornado.web
  
  class BaseHandler(tornado.web.RequestHandler):
      def get(self):
          self.write("ICS Demo")
  
new_contents: import json
  import tornado.web
  
  class BaseHandler(tornado.web.RequestHandler):
      def get(self):
          self.write("ICS Demo")
  
      def json_write(self, obj):
          self.write(json.dumps(obj.__dict__, default=lambda o: o.__dict__))
  
subject: add json_write to BaseHandler