Note pitches are represented as in the MIDI specification, using integers from 0 (lowest pitch) to 127 (highest pitch). That’s a total of 128 pitches (i.e., 10 octaves).

The music library defines the following pitch constants for convenience. The highest possible pitch is G9; it is equal to 127. The lowest possible note is C_1 (C negative one); it is equal to 0.

Additionally, there is a special pitch corresponding to rests:

Rests are notes that last as long as you specify (see duration constants), but produce no sound.