anchor.diff:    # makefun, pytest-*) have circular dependecies.
     doCheck = false;
   
  -  pythonImportsCheck = [ "pytest_cases" ];
  +  pythonImportsCheck = [
  +    "pytest_cases"
  +  ];
   
     meta = with lib; {
       description = "Separate test code from test cases in pytest";
  
positive.code: 
  buildPythonPackage rec {
    pname = "pytest-cases";
    version = "3.6.4";
    disabled = pythonOlder "3.6";
  
    src = fetchPypi {
      inherit pname version;
      sha256 = "sha256-m2oxE7q46TWadhZgpwTAHKep5ZN9LG1VNCRJkPz5W1E=";
    };
  
    nativeBuildInputs = [
  
negative.code:   ];
  
    postPatch = ''
      substituteInPlace setup.cfg \
        --replace "pytest-runner" ""
    '';
  
    # Tests have dependencies (pytest-harvest, pytest-steps) which
  