from django.contrib import admin

from import_export.admin import ImportExportMixin

from .models import Book, Category, Author


class BookAdmin(ImportExportMixin, admin.ModelAdmin):
    list_filter = ['categories', 'author']


admin.site.register(Book, BookAdmin)
admin.site.register(Category)
admin.site.register(Author)

from django.contrib import admin

from import_export.admin import ImportExportMixin

from .models import Book, Category, Author


class BookAdmin(ImportExportMixin, admin.ModelAdmin):
    pass


admin.site.register(Book, BookAdmin)
admin.site.register(Category)
admin.site.register(Author)

--- 
+++ 
@@ -6,7 +6,7 @@
 
 
 class BookAdmin(ImportExportMixin, admin.ModelAdmin):
-    pass
+    list_filter = ['categories', 'author']
 
 
 admin.site.register(Book, BookAdmin)
Add BookAdmin options in test app
