new_contents: from django.contrib import admin
  
  from .models import Letter, Attachment
  
  
  class AttachmentInline(admin.StackedInline):
      '''
          Stacked Inline View for Attachment
      '''
      model = Attachment
  
  
  @admin.register(Letter)
  class LetterAdmin(admin.ModelAdmin):
      '''
          Admin View for Letter
      '''
      list_display = ('title', 'author', 'created', 'modified', 'is_draft', 'is_incoming')
      list_filter = ('created', 'modified')
      inlines = [
          AttachmentInline,
      ]
      search_fields = ('title', 'body')
      readonly_fields = ('message', )
  
      def get_queryset(self, *args, **kwargs):
          qs = super(LetterAdmin, self).get_queryset(*args, **kwargs)
          return qs.with_author()
  
subject: Add LetterAdmin