Can contain tie directions at certain note indices. For example, if it contains {2: PlacementEnum.Below}, then the tie should go downwards from Tie.Notes[2] onwards, even if tie.TieDirection is PlacementEnum.Above (tie starts going up on Notes[0]).
Gets the direction of the tie from the given note to the next one: the direction given at that note, or at the last note before it that gives one (see NoteIndexToTieDirection), else TieDirection.
OptionalstartNote: NoteThe note of the tie that the part starts at. Without it, TieDirection.
The direction, PlacementEnum.NotYetDefined if none is given.
A [[Tie]] connects two notes of the same sounding pitch, indicating that they have to be played as a single note.