anchor.diff:  in buildPythonPackage rec {
     version = "3.7.0";
     pname = "h5py";
  -  disabled = isPy27;
  +  format = "pyproject";
  +
  +  disabled = pythonOlder "3.7";
   
     src = fetchPypi {
       inherit pname version;
  
positive.code: 
    preBuild = if mpiSupport then "export CC=${mpi}/bin/mpicc" else "";
  
    # tests now require pytest-mpi, which isn't available and difficult to package
    doCheck = false;
    checkInputs = lib.optional isPy27 unittest2 ++ [ pytestCheckHook openssh ];
    nativeBuildInputs = [ pkgconfig cython ];
    buildInputs = [ hdf5 ]
      ++ lib.optional mpiSupport mpi;
    propagatedBuildInputs = [ numpy six]
      ++ lib.optionals mpiSupport [ mpi4py openssh ]
      ++ lib.optionals (pythonOlder "3.8") [ cached-property ];
  
    pythonImportsCheck = [ "h5py" ];
  
  
negative.code: { lib
  , fetchPypi
  , buildPythonPackage
  , pythonOlder
  , setuptools
  , numpy
  , hdf5
  , cython
  , pkgconfig
  , mpi4py ? null
  , openssh
  , pytestCheckHook
  , cached-property
  }:
  
  assert hdf5.mpiSupport -> mpi4py != null && hdf5.mpi == mpi4py.mpi;
  
  