anchor.diff:      ++ optional enableKeyfinder     keyfinder-cli
       ++ optional enableLastfm        pythonPackages.pylast
       ++ optional enableMpd           pythonPackages.mpd2
  +    ++ optional enableSonosUpdate   pythonPackages.soco
       ++ optional enableThumbnails    pythonPackages.pyxdg
       ++ optional enableWeb           pythonPackages.flask
       ++ optional enableAlternatives  plugins.alternatives
  
positive.code: , enableLastfm         ? true
  , enableMpd            ? true
  , enableReplaygain     ? true, bs1770gain ? null
  , enableThumbnails     ? true
  , enableWeb            ? true
  
  
negative.code:     mpdstats = enableMpd;
      mpdupdate = enableMpd;
      replaygain = enableReplaygain;
      sonosupdate = enableSonosUpdate;
      thumbnails = enableThumbnails;
      web = enableWeb;
    };
  