anchor.diff:        --replace "SET(CYTHON_BIN cython" "SET(CYTHON_BIN ${cython}/bin/cython"
     '';
   
  -  buildInputs = [ cython cmake ];
  +  nativeBuildUnputs = [ cmake ];
  +
  +  buildInputs = [ cython ];
   
     checkInputs = [ pytest sympy ];
   
  
positive.code: 
  buildPythonPackage rec {
    pname = "symengine";
    version = "0.4.0";
  
    src = fetchFromGitHub {
      owner = "symengine";
      repo = "symengine.py";
      rev = "v${version}";
      sha256 = "07i9rwxphi4zgwc7y6f6qvq73iym2cx4k1bpd7rmd3wkpgrrfxqx";
    };
  
    postConfigure = ''
  
negative.code:     homepage = "https://github.com/symengine/symengine.py";
      license = licenses.mit;
      maintainers = [ maintainers.costrouc ];
    };
  }
  