old_contents: from cendr import app
  
  if __name__ == '__main__':
      # This is used when running locally. Gunicorn is used to run the
      # application on Google App Engine. See entrypoint in app.yaml.
      app.run(host='127.0.0.1', port=8080, debug=True)
  
new_contents: from cendr import app
  
  @app.errorhandler(500)
  def server_error(e):
      logging.exception('An error occurred during a request.')
      return """
      An internal error occurred: <pre>{}</pre>
      See logs for full stacktrace.
      """.format(e), 500
  
  if __name__ == '__main__':
      # This is used when running locally. Gunicorn is used to run the
      # application on Google App Engine. See entrypoint in app.yaml.
      app.run(host='127.0.0.1', port=8080, debug=True)
  
subject: Add exception