* for example:
* Ockeghem: Missa Ecce ancilla domini, bassus part, end of Christe.
*
- * TODO: enhance robustness: in case of an illegal ligature (e.g. the
+ * TODO: enhance robustness: in case of an invalid ligature (e.g. the
* input specifies a ligature that contains a minima), automatically
* break the ligature into smaller, valid pieces. Such a piece may be
* a single note.