anchor.diff:  { stdenv, fetchFromGitHub, writeScript, glibcLocales
  -, pythonPackages, imagemagick
  +, python2Packages, imagemagick
   
   , enableAcousticbrainz ? true
   , enableAcoustid       ? true
  
positive.code:   };
  
    propagatedBuildInputs = [
      pythonPackages.enum34
      pythonPackages.jellyfish
      pythonPackages.munkres
      pythonPackages.musicbrainzngs
      pythonPackages.mutagen
      pythonPackages.pathlib
      pythonPackages.pyyaml
      pythonPackages.unidecode
    ] ++ optional enableAcoustid     pythonPackages.pyacoustid
      ++ optional (enableFetchart
                || enableEmbyupdate
                || enableAcousticbrainz)
                                     pythonPackages.requests2
      ++ optional enableConvert      ffmpeg
      ++ optional enableDiscogs      pythonPackages.discogs_client
      ++ optional enableKeyfinder    keyfinder-cli
      ++ optional enableLastfm       pythonPackages.pylast
      ++ optional enableMpd          pythonPackages.mpd
      ++ optional enableThumbnails   pythonPackages.pyxdg
      ++ optional enableWeb          pythonPackages.flask
      ++ optional enableAlternatives (import ./alternatives-plugin.nix {
        inherit stdenv pythonPackages fetchFromGitHub;
      })
      ++ optional enableCopyArtifacts (import ./copyartifacts-plugin.nix {
        inherit stdenv pythonPackages fetchFromGitHub;
      });
  
    buildInputs = with pythonPackages; [
      beautifulsoup4
      imagemagick
      mock
  
negative.code: , bashInteractive, bash-completion
  }:
  
  assert enableAcoustid    -> python2Packages.pyacoustid     != null;
  assert enableBadfiles    -> flac != null && mp3val != null;
  assert enableConvert     -> ffmpeg != null;
  assert enableDiscogs     -> python2Packages.discogs_client != null;
  assert enableFetchart    -> python2Packages.responses      != null;
  assert enableKeyfinder   -> keyfinder-cli != null;
  assert enableLastfm      -> python2Packages.pylast         != null;
  assert enableMpd         -> python2Packages.mpd            != null;
  assert enableReplaygain  -> bs1770gain                    != null;
  assert enableThumbnails  -> python2Packages.pyxdg          != null;
  assert enableWeb         -> python2Packages.flask          != null;
  
  with stdenv.lib;
  
  