@parameters.argument_decorator
    @modifiers.kwoargs(start='kw')
    def _label(arg, kw, flag=False, kwd='D', i=0):
        raise NotImplementedError
Return a ``diff`` style unified diff listing between the sha_names of
dataset/ETHPy150Open epsy/clize/clize/tests/test_parameters.py/DecoHelpTests._label--crossover with--dataset/ETHPy150Open python-openxml/opc-diag/features/steps/step_data.py/_Manifest.diff