(define-display-method PropertyUnset (expr)
(format #f "~a\\unset ~a~a~a"
(if (ly:music-property expr 'once #f) "\\once " "")
(define-display-method PropertyUnset (expr)
(format #f "~a\\unset ~a~a~a"
(if (ly:music-property expr 'once #f) "\\once " "")