django模型中每个类别的最新条目

from django.db import models

class Category(models.Model):
    name = models.CharField(max_length=100)

class Item(models.Model):
    category = models.ForeignKey(Category, on_delete=models.CASCADE)
    name = models.CharField(max_length=100)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['-created_at']

    @classmethod
    def get_latest_items(cls):
        categories = Category.objects.all()
        latest_items = []
        for category in categories:
            latest_item = cls.objects.filter(category=category).first()
            if latest_item:
                latest_items.append(latest_item)
        return latest_items

latest_items = Item.get_latest_items()
for item in latest_items:
    print(item.category.name, item.name, item.created_at)