anchor.diff:  buildPythonPackage rec {
     pname = "PyWavelets";
     version = "1.1.1";
  +  disabled = isPy27;
   
     src = fetchPypi {
       inherit pname version;
  
positive.code: { lib
  , buildPythonPackage
  , fetchPypi
  , cython
  , nose
  , pytest
  
negative.code:   propagatedBuildInputs = [ numpy ];
  
    # Somehow nosetests doesn't run the tests, so let's use pytest instead
    doCheck = false; # tests use relative paths, which fail to resolve
    checkPhase = ''
      py.test pywt/tests
    '';
  
    # ensure compiled modules are present
    pythonImportsCheck = [
      "pywt"
      "pywt._extensions._cwt"
      "pywt._extensions._dwt"
      "pywt._extensions._pywt"
      "pywt._extensions._swt"
    ];
  
    meta = with lib; {
      description = "Wavelet transform module";
      homepage = https://github.com/PyWavelets/pywt;
      license = licenses.mit;
    };
  
  }
  