anchor.diff:  { lib
   , buildPythonPackage
  -, certifi
   , fetchPypi
   , flaky
  +, httpx
   , importlib-metadata
   , pytestCheckHook
   , pythonOlder
  
positive.code:   ];
  
    propagatedBuildInputs = [
      certifi
    ] ++ lib.optionals (pythonOlder "3.8") [
      importlib-metadata
    ];
  
negative.code: 
  buildPythonPackage rec {
    pname = "pylast";
    version = "5.0.0";
    format = "setuptools";
  
    disabled = pythonOlder "3.7";
  
    src = fetchPypi {
      inherit pname version;
      hash = "sha256-UBi2bCtGMtcavYEDtz5m5N0UxmCaj3un5aomxzbfLfg=";
    };
  
    nativeBuildInputs = [
  