anchor.diff:  { stdenv, fetchurl, pkgconfig, pythonPackages, gettext, texinfo
   , ghostscript, librsvg, gdk-pixbuf, txt2man, timidity, mpg123
   , alsaUtils, vorbis-tools, csound, lilypond
  -, makeWrapper
  +, wrapGAppsHook
   }:
   
  -let
  -  inherit (pythonPackages) python pygtk;
  -in stdenv.mkDerivation rec {
  +pythonPackages.buildPythonApplication rec {
     name = "solfege-3.22.2";
   
     src = fetchurl {
  
positive.code:            default.config
    '';
  
    postInstall = ''
        set -x
        wrapProgram "$out/bin/solfege" \
            --prefix PYTHONPATH ':' "$PYTHONPATH" \
            --set GDK_PIXBUF_MODULE_FILE "$GDK_PIXBUF_MODULE_FILE"
    '';
  
    meta = with stdenv.lib; {
      description = "Ear training program";
  
negative.code:     sha256 = "1r4g93ka7i8jh5glii5nza0zq0wy4sw0gfzpvkcrhj9yr1h0jsp4";
    };
  
    nativeBuildInputs = [ gettext texinfo pkgconfig wrapGAppsHook ];
    buildInputs = [ librsvg ];
    propagatedBuildInputs = [ pythonPackages.pygtk ];
  
    preBuild = ''
      sed -i -e 's|wav_player=.*|wav_player=${alsaUtils}/bin/aplay|' \
  