Function sound_chord_notation 

pub fn sound_chord_notation(
    root: &Pitch,
    kind: &str,
    notation: Option<&str>,
    bass: Option<&Pitch>,
    modifications: &[ChordStepModification],
) -> Result<Vec<Pitch>>

The same with the kind’s notation handed over rather than looked up: music21’s table can be added to while a program runs (addNewChordSymbol), and a kind added there is sounded from the notation it was added with.