new_contents: from django.conf.urls import url
  from cms import views
  
  urlpatterns = [
      # 書籍
      url(r'^book/$', views.book_list, name='book_list'),   # 一覧
      url(r'^book/add/$', views.book_edit, name='book_add'),  # 登録
      url(r'^book/mod/(?P<book_id>\d+)/$',
          views.book_edit, name='book_mod'),  # 修正
      url(r'^book/del/(?P<book_id>\d+)/$',
          views.book_del, name='book_del')   # 削除
  ]
  
subject: add cms/urls.py