- list_display = ('title', 'slug', 'created_at', 'has_epub_file', 'has_html_file', 'has_description',)
+ list_display = (
+ 'title', 'slug', 'created_at', 'has_epub_file', 'has_html_file', 'has_description',
+ )
+ list_filter = [
+ 'print_on_demand',
+ ('wiki_link', BlankFieldListFilter),
+ ('parent', EmptyFieldListFilter),
+ ('media', admin.EmptyFieldListFilter),
+ ]
+ date_hierarchy = 'created_at'