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
  , fetchurl
  , imageio
  , numpy
  , opencv3
  
negative.code: 
  buildPythonPackage rec {
    pname = "imgaug";
    version = "0.4.0";
  
    src = fetchFromGitHub {
      owner = "aleju";
      repo = "imgaug";
      rev = version;
      sha256 = "17hbxndxphk3bfnq35y805adrfa6gnm5x7grjxbwdw4kqmbbqzah";
    };
  
    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\"" ""
    '';
  