问Django:找不到页面

EN

from django.views.generic.detail import DetailView, SingleObjectMixin
from app.models import MyModel

class MyDetails(DetailView, SingleObjectMixin):
    template_name = "app/my_view.html"
    model = MyModel

from django.conf.urls import include, url
from django.contrib   import admin
from app.views import MainList, post_form_upload, MyDetails

urlpatterns = [
    url(r'^$', MainList.as_view(), name="main_list"),
    url(r'^add_something$', post_form_upload, name="add_something"),
    url(r'^my_details/(?P<pk>\d+)$', MyDetails.as_view(), name="my_details"),
]

from django.conf.urls  import url
from django.conf.urls import include, url
from django.contrib   import admin

urlpatterns = [
    (r'^$', include('app.urls')),
    url(r'^admin/', include(admin.site.urls)),
]

Using the URLconf defined in app.urls, Django tried these URL patterns, in this order:
^$ [name='main_list']
^add_something$ [name='add_something']
^my_details/(?P<pk>\d+)$ [name='my_details']
The current URL, my_details, didn't match any of these.