Comment 2 for bug 1458436

urlpatterns = [,
    url(r'^$',
        views.IndexView.as_view(), name='index'),
    url(r'^(?P<instance_id>[^/]+)/create_snapshot/$',
        views.CreateSnapshotView.as_view(),
        name='create_snapshot'),
]

Still gives an error for me? I removed the comma as such:

urlpatterns = [
    url(r'^$',
        views.IndexView.as_view(), name='index'),
    url(r'^(?P<instance_id>[^/]+)/create_snapshot/$',
        views.CreateSnapshotView.as_view(),
        name='create_snapshot'),
]

And it worked!