anchor.diff:  , stdenv
   , fetchPypi
   , python
  +, pythonOlder
   , buildPythonPackage
   , cython
   , gfortran
  
positive.code: , pytest-xdist
  , numpy
  , pybind11
  }:
  
  buildPythonPackage rec {
  
negative.code: 
    nativeBuildInputs = [ cython gfortran meson-python pythran pkg-config wheel ];
  
    buildInputs = [
      numpy.blas
      pybind11
    ] ++ lib.optionals (pythonOlder "3.9") [
      libxcrypt
    ];
  
    propagatedBuildInputs = [ numpy ];
  
  