anchor.diff:  
     nativeBuildInputs = [
       setuptools-scm-git-archive
  -    setuptools_scm
  +    setuptools-scm
     ];
   
     checkInputs = [
       attrs
       hypothesis
  -    pillow
  -    pytestCheckHook
       pytest-helpers-namespace
       pytest-timeout
  -    pytest_xdist
  -    pytestrunner
  +    pytest-xdist
  +    psutil
  +    pytest-cov
  +    pytestCheckHook
       python-dateutil
       python-xmp-toolkit
     ];
   
  -  propagatedBuildInputs = [ defusedxml lxml ];
  -
  -  postPatch = ''
  -    sed -i \
  -      -e 's/^pytest .*/pytest/g' \
  -      -e 's/^attrs .*/attrs/g' \
  -      -e 's/^hypothesis .*/hypothesis/g' \
  -      requirements/test.txt
  -  '';
  +  propagatedBuildInputs = [
  +    defusedxml
  +    lxml
  +    pillow
  +  ];
   
     preBuild = ''
       HOME=$TMPDIR
     '';
  +
  +  pythonImportsCheck = [ "pikepdf" ];
   
     meta = with lib; {
       homepage = "https://github.com/pikepdf/pikepdf";
  
positive.code: , isPy3k
  , lxml
  , pillow
  , pybind11
  , pytestCheckHook
  , pytest-helpers-namespace
  , pytest-timeout
  , pytest_xdist
  , pytestrunner
  , python-dateutil
  , python-xmp-toolkit
  , python3
  , qpdf
  , setuptools-scm-git-archive
  , setuptools_scm
  , lib
  }:
  
  buildPythonPackage rec {
    pname = "pikepdf";
    version = "2.2.0";
    disabled = ! isPy3k;
  
    src = fetchPypi {
      inherit pname version;
      sha256 = "74300a32c41b3d578772f6933f23a88b19f74484185e71e5225ce2f7ea5aea78";
    };
  
    buildInputs = [
  
negative.code: { lib
  , attrs
  , buildPythonPackage
  , defusedxml
  , fetchPypi
  