My brother suggested that there be a whistling module (I'm thinking in Singing would be perfect), to help learn how to whistle in tune and I think that would be awesome! I've always been confused about what octave to whistle in, and it'd be great to learn to how follow music whistling, and I'd love to learn!
You can try Whistling when you calibrate the vocal range and all the workouts somewhat work.
I have tested it a little bit out of curiosity from your feature request. :)