anchor.diff:  
       export XDG_DATA_DIRS=$XDG_DATA_DIRS:${gnome.adwaita-icon-theme}/share
       # build the user manual
  -    PATH=$out/bin:$PATH PAPERWORK_TEST_DOCUMENTS=${sample_documents} make data
  +    PATH=$out/bin:$PATH PAPERWORK_TEST_DOCUMENTS=${sample_docs} make data
       for i in src/paperwork_gtk/model/help/out/*.pdf; do
         install -Dt $site/model/help/out $i
       done
  
positive.code: , texlive
  , imagemagick
  , perlPackages
  }:
  
  let
  
negative.code:     imagemagick
      perlPackages.Po4a
    ];
    inherit (import ./src.nix { inherit fetchFromGitLab; }) version src sample_documents;
  in
  
  python3Packages.buildPythonApplication rec {
    inherit src version;
    pname = "paperwork";
  
    sample_docs = sample_documents // {
      # a trick for the update script
      name = "sample_documents";
      src = sample_documents;
    };
  
    sourceRoot = "source/paperwork-gtk";
  
  