anchor.diff:  
     sourceRoot = "source/paperwork-backend";
   
  -  # Python 2.x is not supported.
  -  disabled = !isPy3k && !isPyPy;
  -
     patchPhase = ''
       echo 'version = "${version}"' > src/paperwork_backend/_version.py
       chmod a+w -R ..
  
positive.code:   '';
  
    propagatedBuildInputs = [
      pyenchant
      scikit-learn
      pypillowfight
      pycountry
      whoosh
      termcolor
      python-Levenshtein
      libinsane
      pygobject3
      pyocr
      natsort
      pkgs.poppler_gi
      pkgs.gtk3
      distro
      openpaperwork-core
    ];
  
    preCheck = ''
      export HOME=$(mktemp -d)
    '';
  
    nativeBuildInputs = [ pkgs.gettext pkgs.which pkgs.shared-mime-info ];
    preBuild = ''
      make l10n_compile
    '';
  
    checkInputs = [ openpaperwork-gtk psutil pkgs.libreoffice ];
  
    meta = {
      description = "Backend part of Paperwork (Python API, no UI)";
      homepage = "https://openpaper.work/";
      license = lib.licenses.gpl3Plus;
      maintainers = with lib.maintainers; [ aszlig symphorien ];
    };
  }
  
negative.code: { buildPythonPackage
  , lib
  , fetchFromGitLab
  , pyenchant
  , scikit-learn
  , pypillowfight
  