P.47 (Add Methods to Control Key Up and Down)
public void whiteKeyDownUp() {
setImage("white-key-down.png");
Greenfoot.playSound(sound);
Greenfoot.delay(15);
setImage("white-key.png");
}
public void blackKeyDownUp() {
setImage ("black-key-down.png");
Greenfoot.playSound(sound);
Greenfoot.delay(15);
setImage ("black-key.png");
}