macOS NSBeep + Screen Flash?

it couldn't be easier to make an app beep during an action by writing NSBeep()... but what about making the screen flash? i've literally search for hours trying to find an answer, but you can imagine that all my search queries came up with threads dealing with adobe's application.

if you don't know what i'm talking about: Sys Prefs > Universal Access > Hearing > Test The Screen Flash.

any suggestions? places to look? answers?

FlashMenuBar(0); FlashMenuBar(0); (written twice) seems to work... but i was under the impression that this makes the menu bar blink if it's called twice... so now how do i make my menubar blink?