new_contents: from app import app
  from feed import Entry, Feed
  from flask import jsonify, render_template
  
  @app.route('/')
  def index():
      return jsonify()
  
  @app.route('/cast/<url>/<index>')
  def feed(url, index):
      """
      :param url: Podcast feed URL.
      :type  url: ``str``
  
      :param index: Index representing the episode number, defaults to latest.
      :type  index: ``int``
      """
      feed = Feed(url=url)
  
      try:
          entry = feed.lookup().get(index)
      except TypeError:
          return jsonify(error_message='index must be an integer.'), 400
      except IndexError:
          return jsonify(error_message='episode {} not found'.format(index)), 400
  
      return jsonify(feed_url=entry.audio)
  
subject: update view.py