old_contents: from django.contrib import admin
  
  from models import ZipCode
  
  admin.site.register(ZipCode)
  
new_contents: from django.contrib import admin
  
  from models import ZipCode
  
  class ZipCodeAdmin(admin.ModelAdmin):
      list_display = ('zip_code', 'latitude', 'longitude', 'state', 'city')
      list_filter = ('state',)
      search_fields = ('zip_code', 'state', 'city')
  
  admin.site.register(ZipCode, ZipCodeAdmin)
  
subject: improve admin interface for zip codes