'Returns the integer rating given to this item by the user.'

def serialize_user_rating(self, item, key, user=None, **context):

    if (not user):
        raise base.ModelSerializingError('user_rating    requires    a    user', model_class=self.manager.model_class, id=self.serialize_id(item, 'id'))
    return self.manager.rating(item, user)
