Problem with a snippet "shorthand for triplets [0.21429]"

[mark damerell]

It came from:
%% http://lsr.di.unimi.it/LSR/Item?id=328

Here is part of it:

% First version, with a single argument, i.e. the
% syntax is \triplet{ c d e }
triplet = #(define-music-function (music) (ly:music?)
  #{ \tuplet 3/2 $music #})

\score{
  \relative c'{
    c4 \triplet {c d e}
  }
}

This produces:

GNU LilyPond 2.18.2
Processing `/home/rmd/Music/holycity/trips.ly'
Parsing.../usr/share/lilypond/2.18.2/scm/ly-syntax-constructors.scm:56:23:
In expression (apply (ly:music-function-extract fun) parser ...):
/usr/share/lilypond/2.18.2/scm/ly-syntax-constructors.scm:56:23: Wrong
number of arguments to #<procedure #f (music)>

Compilation exited abnormally with code 1 at Mon Jun 27 12:18:38

Please any advice? thank you.