我正在 admin.py 中進行導入導出到 excel，每次單擊導入按鈕時，我都會收到此錯誤“CustomerPurchaseOrder”對象沒有屬性“get_user_visible_fields”我不知道我的代碼出了什么問題，我一直在遵循文檔（以下）。我的代碼中遺漏了什么嗎？class CustomerPurchaseOrderResource(resources.ModelResource):    class Meta:        model = CustomerPurchaseOrder        fields = ('profile', 'customer_Purchase_Order_Detail', 'process', 'deliverySchedule', 'deliveryDate', 'paymentmethod',    'requestedDate',)class CustomerPurchaseOrderAdmin(ImportExportModelAdmin):    list_filter = ("process", "deliverySchedule", "inputdate")    list_display = (    'profile', 'customer_Purchase_Order_Detail', 'process', 'deliverySchedule', 'deliveryDate', 'paymentmethod',    'requestedDate',)    ordering = ('id','requestedDate')    resource_class = CustomerPurchaseOrder這是我的 models.pyclass CustomerPurchaseOrder(models.Model):    profile = models.ForeignKey(Customer,                                on_delete=models.SET_NULL, null=True, blank=True,                                verbose_name="Client Account")    customerdeliveryaddress = models.ForeignKey(CustomerDeliveryAddress,                                                 on_delete=models.SET_NULL, null=True, blank=True,                                                verbose_name="Delivery Address")    customer_Purchase_Order_Detail = models.ForeignKey('CustomerPurchaseOrderDetail',                                                       on_delete=models.SET_NULL, null=True, blank=True,                                                       verbose_name="Customer Purchase Order")    process = models.ForeignKey('Process',                                 on_delete=models.SET_NULL, null=True, blank=True,                                verbose_name="Process")