Piano Keys Help

Can someone tell me why when i press Piano key they dont change color ?? whats wrong with my code ?

// The keys and notes variables store the piano keys
const keys = [‘c-key’, ‘d-key’, ‘e-key’, ‘f-key’, ‘g-key’, ‘a-key’, ‘b-key’, ‘high-c-key’, ‘c-sharp-key’, ‘d-sharp-key’, ‘f-sharp-key’, ‘g-sharp-key’, ‘a-sharp-key’];
const notes = ;
keys.forEach(function(key){
notes.push(document.getElementById(key));
})

// Write named functions that change the color of the keys below
const keyPlay = event => event.target.style.backgroundColor = ‘red’;

const keyReturn = event => event.target.style.backgroundColor = ‘’;

// Write a named function with event handler properties
let eventAssignment = note => {
note.onmousedown = () => keyPlay(event);
note.onmouseup = () => keyReturn(event);
}

// Write a loop that runs the array elements through the function
notes.forEach(eventAssignment)

What happens if you write these with callbacks?

note.onmousedown = keyPlay;
note.onmouseup = keyReturn;