)))
Irving Berlin wrote a zillion songs, some of them great ones, and he could only play the piano in one key, and I've heard couldn't play it well in that key.

Yes, Irving Berlin only played in the key of Gb. But he invented a transposing piano and used it to play in all keys You can see him demo it here
https://m.youtube.com/watch?v=bO8VZoRw214


Have Fun!
Peter Gannon
PG Music Inc.