subsequence.harmonic_rhythm

The API reference for between.

between

between(
    low: float,
    high: float,
    step: typing.Optional[float] = None,
) -> HarmonicRhythm

A harmonic rhythm that varies between two lengths (in beats).

Each chord lasts a random length in [low, high]. Pass step to snap those lengths to a grid — e.g. between(WHOLE, 3 * WHOLE, step=WHOLE) gives one, two, or three whole notes, never anything in between.

Reads aloud the way you'd describe it: "between one and three whole notes, in whole-note steps."