anchor.diff:      six
     ];
   
  +  # augmenters requires a significant increase in packages requires
     checkPhase = ''
  -     pytest ./test
  +     pytest ./test --ignore=test/augmenters
     '';
   
     checkInputs = [ opencv3 pytest ];
  
positive.code: 
  buildPythonPackage rec {
    pname = "imgaug";
    version = "0.3.0";
  
    src = fetchurl {
      url = "https://github.com/aleju/imgaug/archive/c3d99a420efc45652a1264920dc20378a54b1325.zip";
      sha256 = "sha256:174nvhyhdn3vz0i34rqmkn26840j3mnfr55cvv5bdf9l4y9bbjq2";
    };
  
    postPatch = ''
      substituteInPlace requirements.txt \
        --replace "opencv-python-headless" ""
      substituteInPlace setup.py \
        --replace "opencv-python-headless" "" 
      substituteInPlace pytest.ini \
        --replace "--xdoctest --xdoctest-global-exec=\"import imgaug as ia\nfrom imgaug import augmenters as iaa\"" ""
    '';
  
negative.code: { buildPythonPackage
  , fetchFromGitHub
  , imageio
  , numpy
  , opencv3
  