Django -从每个组的最新日期检索对象- PersonPhoto

from django.db import models

class PersonPhoto(models.Model):
    group = models.ForeignKey(Group, on_delete=models.CASCADE)
    photo = models.ImageField(upload_to='photos/')
    date_added = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.photo.name

from django.db.models import Max
from .models import PersonPhoto

def get_latest_photos_by_group():
    latest_photos = PersonPhoto.objects.values('group').annotate(max_date=Max('date_added'))
    result = []
    for photo in latest_photos:
        latest_photo = PersonPhoto.objects.filter(group=photo['group'], date_added=photo['max_date']).first()
        result.append(latest_photo)
    return result