anchor.diff:  buildPythonPackage rec {
     pname = "imageio";
     version = "2.8.0";
  +  disabled = isPy27;
   
     src = fetchPypi {
       sha256 = "fb5fd6d3d17126bbaac9af29fe340e2c97a196eb9416d4f28c0e543744a152cf";
  
positive.code:   checkInputs = [ pytest psutil ] ++ stdenv.lib.optionals isPy3k [
      imageio-ffmpeg ffmpeg_3
      ];
    propagatedBuildInputs = [ numpy pillow ] ++ stdenv.lib.optionals (!isPy3k) [
      futures
      enum34
      pathlib
    ];
  
    checkPhase = ''
      export IMAGEIO_USERDIR="$TMP"
  
negative.code: { stdenv
  , buildPythonPackage
  , isPy27
  , pathlib
  , fetchPypi
  , pillow
  