anchor.diff:  { lib, buildPythonPackage, fetchFromGitHub, xdg_utils
   , requests, filetype, pyparsing, configparser, arxiv2bib
   , pyyaml, chardet, beautifulsoup4, colorama, bibtexparser
  -, pylibgen, click, python-slugify, habanero, isbnlib
  +, click, python-slugify, habanero, isbnlib, typing-extensions
   , prompt_toolkit, pygments, stevedore, tqdm, lxml
  -, python-doi, isPy3k, pythonOlder
  +, python-doi, isPy3k, pythonOlder, pytestcov
   #, optional, dependencies
   , whoosh, pytest
   , stdenv
  
positive.code:   postPatch = ''
      substituteInPlace setup.py \
        --replace "lxml<=4.3.5" "lxml~=4.3" \
        --replace "python-slugify>=1.2.6,<4" "python-slugify"
    '';
  
  
negative.code:   checkPhase = ''
      HOME=$(mktemp -d) pytest papis tests --ignore tests/downloaders \
        -k "not test_get_data and not test_doi_to_data and not test_general and not get_document_url \
        and not test_validate_arxivid and not test_downloader_getter and not match"
    '';
  
    meta = {
  