anchor.diff:      owner = "mwouts";
       repo = pname;
       rev = "v${version}";
  -    sha256 = "sha256-S2SKAC2oT4VIVMMDbu/Puo87noAgnQs1hh88JphutA8=";
  +    sha256 = "sha256-HzWAEy7z3qi+lSD3yVBGYclfvKTkG1fTsG29NlKPgQw=";
     };
   
     buildInputs = [
  
positive.code: 
  buildPythonPackage rec {
    pname = "jupytext";
    version = "1.13.2";
    format = "pyproject";
  
    disabled = pythonOlder "3.6";
  
negative.code:   postPatch = ''
      # https://github.com/mwouts/jupytext/pull/885
      substituteInPlace setup.py \
        --replace "markdown-it-py~=1.0" "markdown-it-py>=1.0.0,<3.0.0"
    '';
  
    preCheck = ''
  