old_contents: from flask import Flask
  from flask_restful import Resource, Api
  
  app = Flask(__name__)
  api = Api(app)
  
  
  class HelloWorld(Resource):
      def get(self):
          return {'hello': 'world'}
  
  api.add_resource(HelloWorld, '/')
  
  if __name__ == '__main__':
      app.run(debug=True)
  
new_contents: from flask import Flask
  from flask_restful import Resource, Api
  from app.resources.message import Message
  
  app = Flask(__name__)
  api = Api(app)
  
  
  class HelloWorld(Resource):
      def get(self):
          return {'hello': 'world'}
  
  api.add_resource(HelloWorld, '/')
  api.add_resource(Message, '/message/<int:id>')
  
  if __name__ == '__main__':
      app.run(debug=True)
  
subject: Fix api