当我单击任何项目详细信息页面时，我收到此错误。必须在urlconf中使用对象pk或slug调用通用详细信息视图。
网址：

path('item/<slug:item_slug>/', ItemDetailView.as_view(), name='item_detail'),

视图：

class ItemDetailView(DetailView):
    model = Item
    slug_field = 'item_slug'

型号：

class Item(models.Model):
    title = models.CharField(max_length=100)
    description= RichTextField(blank=True, null=True)
    main_image= models.ImageField(null=True, blank=True,upload_to='images/')
    date = models.DateTimeField(auto_now_add=True)
    item_category = models.ForeignKey(Categories, default='Coding', on_delete=SET_DEFAULT)
    slug = models.SlugField(unique=True, blank=True, null=True) # new

    def save(self, *args,**kwargs):
        if not self.slug and self.title:
            self.slug = slugify(self.title)
        super(Item, self).save(*args,**kwargs)

    def __str__(self):
        return self.title