old_contents: import webapp2
  
  from google.appengine.api import channel
  from google.appengine.api import users
  
  class Channel(webapp2.RequestHandler):
      def get(self):
          user = users.get_current_user()
          if not user:
              self.response.write({"token": ""})
              return
          token = channel.create_channel(user.user_id())
          self.response.write({"token": token})
  
  app = webapp2.WSGIApplication([
      ('/api/channel', Channel),
  ])
  
new_contents: import webapp2
  
  from google.appengine.api import channel
  from google.appengine.api import users
  
  class Channel(webapp2.RequestHandler):
      def get(self):
          user = users.get_current_user()
          if not user:
              self.response.write({"token": ""})
              return
          token = channel.create_channel(user.user_id())
          channel.send_message(user.user_id(), "hello")
          self.response.write({"token": token})
  
  app = webapp2.WSGIApplication([
      ('/api/channel', Channel),
  ])
  
subject: Send a message back to client