The LilyPond markup language appears not to be working in the case of Chopin's Second Nocturne. https://en.wikisource.org/wiki/Chopin_Nocturnes_Opus_9/Number_2
The encoded musical score works well enough to generate a midi file, but the musical score does not appear on the page as it should (there is an error message).
https://en.wikisource.org/wiki/User_talk:Beeswaxcandle#LilyPond