通过反向过滤queryset，在Django中存在检查

I have models:

我有模型:

class Post(models.Model):
    content = models.CharField()
    user = models.ForeignKey('users.User')
    active = models.BooleanField(default=True)

class Comment(models.Model):
    post = models.ForeignKey(Post, related_name='post_comments')
class Post(models.Mode