new_contents: from boomerang import Messenger, messages
  
  VERIFY_TOKEN = 'secret_code'
  PAGE_TOKEN = 'EAADJEe1tgFsBAAAT2Tz2ONZAqb2bbfbgiMKZASZBzoCZCmKuD5R4RUeJPbgsLkHSA5yd621CTWcRD0kwuAZCSKgjLtFJvPorpsct62oyFdjsUZBDm80aJcLMSNDtr3mqlH5SJeqPF8PyrL4UMtC0cZArQZAou1WwykkZCy8ABJlYRkAZDZD'
  
  
  class EchoServer(Messenger):
  
      async def message_received(self, message):
  
          # Print the received message
          print('\nReceived message from {0}'.format(message.user_id))
          print('> {0}'.format(message.text))
  
          # Create a Message object with the text received
          reply = messages.Message(text=message.text)
  
          # Send the new Message object
          message_id = await self.send(message.user_id, reply)
  
          print('Reply sent with message id: {0}'.format(message_id))
  
  
  app = EchoServer(VERIFY_TOKEN, PAGE_TOKEN)
  app.run(hostname='0.0.0.0', debug=True)
  
subject: Add example echo server