urlpatterns = [
url(r'^publish/(\d+)/$', views.publish, name="youtube_publish"),
+ path('book/<slug:slug>/publish/', views.book_publish, name="youtube_book_publish"),
path('thumbnail/<int:aid>/', views.thumbnail, name='youtube_thumbnail'),
path('thumbnail/<int:aid>/<int:thumbnail_id>/', views.thumbnail, name='youtube_thumbnail'),
path('preview/<int:pk>/', views.Preview.as_view(), name="youtube_preview"),