code: def create_reference_server_flask_app(cfg):
      
      # Create Flask app
      app = Flask(__name__)
      Flask.secret_key = "SECRET_HERE"
      app.debug = cfg.debug
      # Install request handlers
      client_prefixes = dict()
      for api_version in cfg.api_versions:
          handler_config = Config(cfg)
          handler_config.api_version = api_version
          handler_config.klass_name = 'pil'
          handler_config.auth_type = 'none'
          # Set same prefix on local server as expected on iiif.io
          handler_config.prefix = "api/image/%s/example/reference" % (api_version)
          handler_config.client_prefix = handler_config.prefix
          add_handler(app, handler_config)
      return app
docs: Create referece server Flask application with one or more IIIF handlers.