code: def get_success_url(self, obj=None):
          
          if self.success_endpoint is None:
              raise AttributeError('You must assign the value of the attribute "success_endpoint".')
  
          if obj:
              kwargs = {p: getattr(obj, p) for p in get_route_param_names(self.success_endpoint)}
          else:
              kwargs = {}
  
          return url_for(self.success_endpoint, **kwargs)
docs: Args:
              obj (object): The object whose property values are used to build the URL.
  
          Returns:
              str: The URL to which to go if the form was processed successfully.