code cleanup.

moved process_comic_book to static method.

comic/admin.py

@@ -1,7 +1,7 @@
 from django.contrib import admin
 from comic.models import Setting, ComicBook, ComicPage
 
-# Register your models here.
+
 @admin.register(Setting)
 class SettingAdmin(admin.ModelAdmin):
     list_display = ('name', 'value')
@@ -11,7 +11,8 @@ class SettingAdmin(admin.ModelAdmin):
 class ComicBookAdmin(admin.ModelAdmin):
     list_display = ('file_name', 'last_read_page')
 
+
 @admin.register(ComicPage)
 class ComicPageAdmin(admin.ModelAdmin):
     list_display = ('Comic', 'index', 'page_file_name', 'content_type')
-    list_filter = ['Comic']
+    list_filter = ['Comic']