anchor.diff:      fonttools
       # required by fonttools[ufo]
       fs
  +  ] ++ lib.optionals (pythonOlder "3.11") [
  +    exceptiongroup
     ] ++ lib.optionals (pythonOlder "3.8") [
       importlib-metadata
     ];
  
positive.code: , attrs
  , buildPythonPackage
  , cattrs
  , fetchFromGitHub
  , fonttools
  , fs
  
negative.code:   src = fetchFromGitHub {
      owner = "daltonmaag";
      repo = pname;
      rev = "refs/tags/v${version}";
      sha256 = "sha256-BpxjAr65ZQEJ0PSUIPtS78UvJbMG91qkV8py2K/+W2E=";
    };
  
    nativeBuildInputs = [
  