old_contents: from flask import Flask
  
  app = Flask(__name__)
  app.config.from_object(__name__)
  app.config.update(dict(
      SECRET_KEY='development key',
      USERNAME='admin',
      PASSWORD='default'
  ))
  
new_contents: from flask import Flask
  
  app = Flask(__name__)
  app.config.from_object(__name__)
  app.config.update(dict(
      SECRET_KEY='development key',
      USERNAME='admin',
      PASSWORD='default'
  ))
  
  
  @app.route('/', methods=['GET'])
  def front_page():
      return 'Hello, World!'
  
subject: Add route '/' with Hello World