old_contents: 'use strict';
  var $ = require('jquery');
  var _ = require('underscore');
  var Backbone = require('backbone');
  Backbone.$ = $;
  var Mn = require('backbone.marionette');
  var app = Mn.Application();
  
new_contents: 'use strict';
  var $ = require('jquery');
  var Backbone = require('backbone');
  Backbone.$ = $;
  var Mn = require('backbone.marionette');
  var app = Mn.Application();
  
subject: remove unnecessary import