Deploy React app on Heroku – how to jump one folder up

Solution
  def create_app(test_config=None):

  app = Flask(__name__, static_folder='../frontend/build', static_url_path='')
  print(app.static_folder)
  
  setup_db(app)
  CORS(app)

  @app.route('/')
  def index():
    return send_from_directory(static_folder, 'index.html')

  return app