#(define bookpart-score-handler ly:book-add-score!)
#(define bookpart-text-handler ly:book-add-score!)
#(define bookpart-music-handler collect-book-music-for-book)
#(define bookpart-score-handler ly:book-add-score!)
#(define bookpart-text-handler ly:book-add-score!)
#(define bookpart-music-handler collect-book-music-for-book)