text: from flask import Flask
  app = Flask(__name__)
  
  @app.route('/')
  def index():
      return '<h1>Hello World!</h1>'
  
  @app.route('/user/<name>')
  def user(name):
      return '<h1>Hello, %s!</h1>' % name
  
  if __name__ == '__main__':
      app.run(debug=True)