Supporting Continuity Camera

To support Continuity Camera I am creating a special NSMenuItem with

item.identifier = NSMenuItem.importFromDeviceIdentifier

When the menu is selected I would suspect the event to trigger Continuity Camera and then provide the data via responder chain to the NSViewController

 class MainViewController : NSViewController {
 
   override func validRequestor(forSendType sendType: NSPasteboard.PasteboardType?, returnType: NSPasteboard.PasteboardType?) -> Any? {
 
    print("validRequestor")
 
    if let pasteboardType = returnType, NSImage.imageTypes.contains(pasteboardType.rawValue) {
      return self
    } else {
      return super.validRequestor(forSendType: sendType, returnType: returnType)
    }
  }

But given that this is not triggering anything I am wondering what I might be missing.

Any pointers?

	class MainViewController : NSViewController {

	override func validRequestor(forSendType sendType: NSPasteboard.PasteboardType?, returnType: NSPasteboard.PasteboardType?) -> Any? {

	print("validRequestor")

	if let pasteboardType = returnType, NSImage.imageTypes.contains(pasteboardType.rawValue) {
	return self
	} else {
	return super.validRequestor(forSendType: sendType, returnType: returnType)
	}
	}