我正在嘗試創建一個聊天室。這是我的代碼。def make_chatroom(request, user_one, user_two):    user_one = user_models.User.objects.get_or_none(pk=user_one)    user_two = user_models.User.objects.get_or_none(pk=user_two)    if user_one is not None and user_two is not None:    try:        conversation = models.Conversation.objects.filter(            participants=user_one        ).filter(participants=user_two)        print(conversation)    except models.Conversation.DoesNotExist:            conversation = models.Conversation.objects.create()            conversation.participants.add(user_one, user_two)    return redirect(reverse("conversations:detail", kwargs={"pk": conversation.pk}))但“QuerySet”對象沒有屬性“pk”發生錯誤。user_one 存在，user_two 也存在。and print 子句打印<QuerySet [<對話：大師，測試>]>我該如何解決？我的模型.py：class Conversation(core_models.TimeStampedModel):    participants = models.ManyToManyField(        "users.User", related_name="converstation", blank=True    )    def __str__(self):        usernames = []        for user in self.participants.all():            usernames.append(user.username)        return ", ".join(usernames)    def count_messages(self):        return self.messages.count()    count_messages.short_description = "??? ?"    def count_participants(self):        return self.participants.count()    count_participants.short_description = "??? ?"class Message(core_models.TimeStampedModel):    message = models.TextField()    user = models.ForeignKey(        "users.User", related_name="messages", on_delete=models.CASCADE    )    conversation = models.ForeignKey(        "Conversation", related_name="messages", on_delete=models.CASCADE    )    def __str__(self):        return f"{self.user} says: {self.message}"