pub fn beat_depths(part: &Stream) -> Result<Vec<(usize, u8)>>Expand description
How many levels of the metrical hierarchy start at each note and rest of
a part’s measures, as positions in Stream::leaves beside the count:
the depths music21’s labelBeatDepth marks.
Each measure is read in the meter it states, else the one in force where it starts, else four-four, nested three levels deep, and every note, chord and rest it holds itself – not those in its voices – is counted where it starts. A note ending a tie is passed over.
§Errors
A note standing outside its measure’s bar.