code: def my_application(api):
      
      device = api.list_connected_devices().first()
      print('using device #', device.id)
      api.delete_device_subscriptions(device.id)
  
      try:
          print('setting webhook url to:', ngrok_url)
          api.update_webhook(ngrok_url)
          print('requesting resource value for:', resource_path)
          deferred = api.get_resource_value_async(device_id=device.id, resource_path=resource_path)
          print('waiting for async #', deferred.async_id)
          result = deferred.wait(15)
          print('webhook sent us this payload value:', repr(result))
          return result
      except Exception:
          print(traceback.format_exc())
      finally:
          api.delete_webhook()
          print("Deregistered and unsubscribed from all resources. Exiting.")
          exit(1)
docs: An example application.
  
      - Registers a webhook with mbed cloud services
      - Requests the value of a resource
      - Prints the value when it arrives