This package provides a Python library ly containing various Python modules to parse, manipulate or create documents in LilyPond format. A command line program ly is also provided that can be used to do various manipulations with LilyPond files. The LilyPond format is a plain text input format that is used by the GNU music typesetter LilyPond (www.lilypond.org). The python-ly package is Free Software, licensed under the GPL. This package is written by the Frescobaldi developers and is used extensively by the Frescobaldi project. The main author is Wilbert Berendsen.