anchor.diff:  , stdenv
   , buildPythonPackage
   , fetchFromGitHub
  -, isPy27
  -, pytest-runner
  +, pythonOlder
   , pytestCheckHook
   , numpy
   , pillow
  +, setuptools
   }:
   
   let
  
positive.code: in
  buildPythonPackage {
    inherit pname version src;
    disabled = isPy27;
  
    propagatedBuildInputs = [ numpy pillow ];
  
    checkInputs = [ pytest-runner pytestCheckHook ];
  
    # Setting $HOME to prevent pytest to try to create a folder inside
    # /homeless-shelter which is read-only.
  
negative.code:     sha256 = "sha256-iExy+mUs1uqs/u9N6btlqyP6/TvoPVsuOuzs56zZAS8=";
    };
  
    # Pydicom needs pydicom-data to run some tests. If these files aren't downloaded
    # before the package creation, it'll try to download during the checkPhase.
    test_data = fetchFromGitHub {
      owner = "${pname}";
  