code: def serve_assets(path):
      
      res = os.path.join(app.config['NIKOLA_ROOT'],
                         _site.config["OUTPUT_FOLDER"], 'assets')
      return send_from_directory(res, path)
docs: Serve Nikola assets.
  
      This is meant to be used ONLY by the internal dev server.
      Please configure your web server to handle requests to this URL::
  
          /assets/ => output/assets