Can I add a column to indicate whether a file has embedded album art?

I would like to be able to detgermine which of my files do not have embedded album art in them. Ideally, I would like to have a column in mp4 that inidcates this. I saw in another thread that it was suggested I create a column with value $covers() to accomplish this. Unfortunately, I can't get this to work as I simply see the literal value $covers(). ANy suggestions on what I am doing incorrectly?

Thank you

That's outdated.
You can find the new value in the help file. You click on "Help" in the Customize columns window and you get the list of placeholders.

Fantastic. Works like a champ. Thank you!