Python 来自每个（发送方、接收方）对的最后消息-django

这是我的models.py文件

class Message(models.Model): 
    sender = models.ForeignKey(User, related_name='user_sent_msgs', on_delete=models.CASCADE)
    receiver = models.ForeignKey(User, related_name='user_received_msgs', on_delete=models.CASCADE)
    text = models.CharField(max_length=255)
    sent = models.DateTimeField(auto_now_add=True)

我需要列出每个聊天（发送者、接收者）对的最后一条消息，如：

id      sender  receiver    text    sent
1       user1   user2       hi      ...
78      user3   user1       ...     ...
322     user11  user1       ...     ...
1231    user1   user4       ...     ...

以下是生成该列表的代码：

def get_queryset(self):
    users = set()
    msgs = Message.objects.filter(Q(sender=user) | Q(receiver=user)).order_by('-sent')
    res = []
    for msg in msgs:
        if msg.sender == user and msg.receiver.id not in users:
            users.add(msg.receiver.id)
            res.append(msg.id)
        elif msg.receiver == user and msg.sender.id not in users:
            users.add(msg.sender.id)
            res.append(msg.id)
    self.queryset = Message.objects.filter(pk__in=res).order_by('-sent')

上面的代码正在运行，但正在寻找更专业、更干净的python（django orm）代码

有没有最优的解决方案