Create a new scene onkeyevent

Hello i am trying to create a scene graph screen on key event but i am getting an error. How in theory we could do such a job?

Key event handling is easy to set up in XML by including an onKeyEvent() function in the element. When the XML component or its children have the key focus, the onKeyEvent() function will be called whenever an unhandled key event bubbles up the focus chain to the XML component.
https://sdkdocs.roku.com/pages/viewpage.action?pageId=1608547