+#(define book-bookpart-handler ly:book-add-bookpart!)
+#(define book-music-handler collect-book-music-for-book)
+#(define book-score-handler ly:book-add-score!)
+#(define book-text-handler ly:book-add-score!)
+
+#(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)
+
+\include "predefined-fretboards-init.ly"