def METHOD_NAME(self, idea):
    if "request" in self.context:
        user = self.context["request"].user
        if user.is_authenticated:
            ct = ContentType.objects.get_for_model(idea)
            ratings = Rating.objects.filter(
                content_type_id=ct.id, object_pk=idea.pk, creator=user
            )
            if ratings.exists():
                return RatingSerializer(ratings.first()).data
    return None