python3 Django 環境下，如果你遇到namespace沒有註冊以及在根目錄下urls.py中的include方法的第二個參數namespace添加之後就出錯的問題。

出錯問題：

‘Specifying a namespace in include() without providing an app_name ‘

django.core.exceptions.ImproperlyConfigured: 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.

解決方法：

請在[app_name]目錄下的urls.py中的urlpatterns前面加上app_name=‘[app_name]‘， [app_name]代表你的應用的名稱。可以參考這篇：https://stackoverflow.com/questions/14892462/django-error-upolls-is-not-a-registered-namespace

解決：Specifying a namespace in include() without providing an app_name和XXX is not a registered namespace問題