Write a function called createMelody(), which returns a phrase of
notes with pitches and durations randomly selected from a scale
and a list, respectively. The function should accept three parameters,
namely, numNotes, scale, and durations (a list of durations) to choose
from. For example, the following call
phrase = createMelody(10, PENTATONIC_SCALE, [QN, SN, EN])
should generate a phrase of 10 notes from the pentatonic scale with
durations randomly selected from the provided list. (Hint: See the
“Pentatonic Melody Generator” case study in Chapter 6.)