anchor.diff:  
   buildPythonPackage rec {
     pname = "imgaug";
  -  version = "0.3.0";
  +  version = "0.4.0";
   
  -  src = fetchurl {
  -    url = "https://github.com/aleju/imgaug/archive/c3d99a420efc45652a1264920dc20378a54b1325.zip";
  -    sha256 = "sha256:174nvhyhdn3vz0i34rqmkn26840j3mnfr55cvv5bdf9l4y9bbjq2";
  +  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" "" 
  +      --replace "opencv-python-headless" ""
       substituteInPlace pytest.ini \
         --replace "--xdoctest --xdoctest-global-exec=\"import imgaug as ia\nfrom imgaug import augmenters as iaa\"" ""
     '';
  
positive.code:     six
    ];
  
    checkPhase = ''
       pytest ./test
    '';
  
    checkInputs = [ opencv3 pytest ];
  
negative.code: { buildPythonPackage
  , fetchFromGitHub
  , imageio
  , numpy
  , opencv3
  