获取不同模型实例的用户输入评分平均值(Django)

from django.db import models

class Rating(models.Model):
    user_id = models.IntegerField()
    instance_id = models.IntegerField()
    score = models.FloatField()

from django.db.models import Avg

def get_average_rating(request):
    average_ratings = Rating.objects.values('instance_id').annotate(avg_score=Avg('score'))
    return JsonResponse({'average_ratings': list(average_ratings)})

from django.urls import path

urlpatterns = [
    path('average-rating/', get_average_rating, name='average-rating'),
]