new_contents: import flask
  from flask import session
  import flask_simple_login
  
  app = flask.Flask(__name__)
  flask_simple_login.init_login(app)
  # Generate a secret key like so:  import os; os.urandom(17)
  app.secret_key = 'a unique secret string used to encrypt sessions'
  
  @app.route('/')
  @flask_simple_login.require_login(redirect=True)
  def index():
      return 'You are logged in as: {}'.format(session.get('username', None))
  
  if __name__ == '__main__':
      # Bind to PORT if defined, otherwise default to 3000.
      app.run(host='0.0.0.0', port=3000, debug=True)
  
subject: add demo