Django：如何为每个外键选择有限数量的行？

class Comment (models.Model):
        user = models.ForeignKey(User, related_name="comments")
        title = models.TextField(max_length=256)
        comment = models.TextField(max_length=1286)
        created = models.DateTimeField(db_index=True)
class Comment (models.Model):
        user = mo