@parameters.argument_decorator
    @modifiers.kwoargs(start='kw')
    def _subst(arg, kw, flag=False, kwd='D', i=0):
        raise NotImplementedError
Qualifies {param.display_name}:
dataset/ETHPy150Open epsy/clize/clize/tests/test_parameters.py/DecoHelpTests._subst