def METHOD_NAME(self, instance):
    data = super().METHOD_NAME(instance)
    target_model = instance.content_type.model_class()
    # when used with the comment viewset it shouldn't be possible to get StopIteration here
    # because other than commentable models are excluded in the viewset
    data['target_type'] = next(api_name for api_name, model in COMMENTABLE_MODELS.items() if model == target_model)
    return data