Write a function named createCantusVoice(), which returns a phrase
containing one of the voices in Arvo Part’s “Cantus in Memoriam”
seen in Chapter 4. The function should accept three parameters,
namely, pitches, durations, and an elongationAmount (a float). For
example, the following
pitches = [A5, G5, F5, E5, D5, C5, B4, A4]
durations = [HN, QN, HN, QN, HN, QN, HN, QN]
voice = createCantusVoice(pitches, durations, 1.0)
should generate a phrase with 8 notes starting with an A5 half note
(HN), followed by a G5 quarter note (QN),... and ending with an A4
quarter note. Whereas the following
voice = createCantusVoice(pitches, durations, 2.0)
should generate a phrase with 8 notes starting with an A5 whole
note (WN), followed by a G5 half note (HN),... and ending with an
A4 half note. (Hint: You may use Mod.elongate() in the body of your
function.)