code: def finalcallback(request, **kwargs):
      
      default_provider.load_services()
      service_name = kwargs.get('service_name')
      service_object = default_provider.get_service(service_name)
      lets_callback = getattr(service_object, 'callback')
      # call the auth func from this class
      # and redirect to the external service page
      # to auth the application django-th to access to the user
      # account details
      return render_to_response(lets_callback(request))
docs: let's do the callback of the related service after
          the auth request from UserServiceCreateView