Django2.0异常：'Specifying a namespace in include() without providing an app_name '

from django.contrib import admin
from django.urls import path,include
import blogtest.views as bv

urlpatterns = [
    path('admin/', admin.site.urls),
    path('index/', include('blogtest.urls',namespace = 'blogtest')),
]

具体的错误是：

'Specifying a namespace in include() without providing an app_name is not supported. Set the app_name attribute in the included module, or pass a 2-tuple containing the list of patterns and app_name instead.'
 

从include()函数可以看出来，这个函数有两个参数，一个arg，一个namespace，我在代码中也是两个参数，但是异常中提示了，没有提供app_name,还提示需要传入一个两元元组，

urlconf_module, app_name = arg

可以看出来，arg就是那个元组，且给app_name赋值了，所以我们这里修改代码为：

from django.contrib import admin
from django.urls import path,include
import blogtest.views as bv

urlpatterns = [
    path('admin/', admin.site.urls),
    path('index/', include(('blogtest.urls','blogtest'),namespace = 'blogtest')),
]