old_contents: from django_assets import Bundle, register
  
  js = Bundle('jquery/dist/jquery.js',
              'bootstrap-sass/assets/javascripts/bootstrap.js',
              filters='uglifyjs',
              output='app.js')
  register('script', js)
  
  css = Bundle('style/id.scss',
               filters='scss',
               depends=['**/*.scss'],
               output='style.css')
  register('style', css)
  
new_contents: from django_assets import Bundle, register
  
  js = Bundle('jquery/dist/jquery.js',
              'bootstrap-sass/assets/javascripts/bootstrap.js',
              output='app.js')
  register('script', js)
  
  css = Bundle('style/id.scss',
               filters='scss',
               depends=['**/*.scss'],
               output='style.css')
  register('style', css)
  
subject: Remove uglifyjs.