anchor.diff:        simplegeneric
       ];
   
  +    doCheck = !stdenv.isDarwin;
  +
       checkInputs = [
  -      pytest
  +      pytestCheckHook
       ];
   
       meta = {
  
positive.code: , cffi
  , tzlocal
  , simplegeneric
  , pytest
  , extraRPackages ? []
  }:
  
  buildPythonPackage rec {
      version = "3.3.6";
      pname = "rpy2";
  
      disabled = isPyPy;
      src = fetchPypi {
        inherit version pname;
        sha256 = "0xvfkxvh01r5ibd5mpisp8bz385hgpn27b988y8v65z7hqr3y1nf";
      };
  
      buildInputs = [
        R
        pcre
        lzma
        bzip2
        zlib
        icu
  
        # is in the upstream `requires` although it shouldn't be -- this is easier than patching it away
        pytest
      ] ++ (with rPackages; [
        # packages expected by the test framework
        ggplot2
  
negative.code:       tidyr
      ]) ++ extraRPackages ++ rWrapper.recommendedPackages;
  
      nativeBuildInputs = [
        R # needed at setup time to detect R_HOME (alternatively set R_HOME explicitly)
      ];
  
      propagatedBuildInputs = [
        ipython
  