def METHOD_NAME(self):
    groups = [copy.deepcopy(grp)
              for grp in nrml.to_python(ALT_MFDS, conv)]
    # there are a SimpleFaultSource and a CharacteristicFaultSource
    fd, fname = tempfile.mkstemp(suffix='.xml')
    with os.fdopen(fd, 'wb'):
        write_source_model(fname, groups, 'Test Source Model')
    # NB: without Node.__deepcopy__ the serialization would fail
    # with a RuntimeError: maximum recursion depth exceeded while
    # calling a Python object