anchor.diff:    src = fetchFromGitHub {
       owner = "sampsyo";
       repo = "beets";
  -    rev = "10d7a6f46ac58d40bc12661d943d2e3ae24761cd";
  -    sha256 = "0e978aa1ccf49b18a6a1914199c8b3110efcaa2c52bc6682c214e0f2fcd0fa7a";
  +    rev = "4c4d8cff60b574296194075bce54a05d017f053b";
  +    sha256 = "90dbbdd1fc3912bb3cefa247ab6b45971ae477d3c099a23aa05e04512a89a27c";
     };
   
     nativeBuildInputs = [
  
positive.code: , pycountry
  
  # External plugins
  , enableAlternatives ? true
  #, enableArtistCountry ? true
  #, enableCopyArtifacts ? true
  , enableDsedivecBeetsPlugins ? true
  }:
  
  let
    inherit (stdenv)
      targetSystem;
    inherit (stdenv.lib)
      attrNames
      concatMapStrings
  
negative.code:     werkzeug
    ] ++ optionals isPy27 [
      enum34
    ] ++ optionals (versionOlder pythonPackages.python.channel "3.5") [
      pathlib
    ] ++ [
      pycountry
  