anchor.diff:      python.modules.readline
     ] ++ optional enableAcoustid     pythonPackages.pyacoustid
       ++ optional (enableFetchart
  -              || enableEmbyupdate) pythonPackages.requests2
  +              || enableEmbyupdate
  +              || enableAcousticbrainz)
  +                                   pythonPackages.requests2
       ++ optional enableDiscogs      pythonPackages.discogs_client
       ++ optional enableEchonest     pythonPackages.pyechonest
       ++ optional enableLastfm       pythonPackages.pylast
  
positive.code: 
  let
    optionalPlugins = {
      badfiles = enableBadfiles;
      chroma = enableAcoustid;
      discogs = enableDiscogs;
  
negative.code: { stdenv, fetchFromGitHub, writeScript, glibcLocales
  , buildPythonPackage, pythonPackages, python, imagemagick
  
  , enableAcousticbrainz ? true
  , enableAcoustid       ? true
  , enableBadfiles       ? true, flac ? null, mp3val ? null
  , enableDiscogs        ? true
  , enableEchonest       ? true
  , enableEmbyupdate     ? true
  , enableFetchart       ? true
  , enableLastfm         ? true
  , enableMpd            ? true
  , enableReplaygain     ? true, bs1770gain ? null
  , enableThumbnails     ? true
  , enableWeb            ? true
  
  # External plugins
  , enableAlternatives ? false
  