anchor.diff:  , pyyaml, chardet, beautifulsoup4, colorama, bibtexparser
   , pylibgen, click, python-slugify, habanero, isbnlib
   , prompt_toolkit, pygments, stevedore, tqdm, lxml
  -, python-doi, isPy3k
  +, python-doi, isPy3k, pythonOlder
   #, optional, dependencies
   , whoosh, pytest
   , stdenv
  
positive.code: buildPythonPackage rec {
    pname = "papis";
    version = "0.9";
  
    # Missing tests on Pypi
    src = fetchFromGitHub {
  
negative.code:     whoosh
    ];
  
    postPatch = ''
      substituteInPlace setup.py \
        --replace "lxml<=4.3.5" "lxml~=4.3" \
        --replace "python-slugify>=1.2.6,<4" "python-slugify"
    '';
  
    # pytest seems to hang with python3.8
    doCheck = !stdenv.isDarwin && pythonOlder "3.8";
  
    checkInputs = ([
      pytest
  