(hash-table? ly:music? pair? string-or-pair?)
(_i "Add predefined fret diagram defined by @var{diagram-definition}
for the chord pitches @var{chord} and the stringTuning @var{tuning}.")
(hash-table? ly:music? pair? string-or-pair?)
(_i "Add predefined fret diagram defined by @var{diagram-definition}
for the chord pitches @var{chord} and the stringTuning @var{tuning}.")