'A :class:`werkzeug.datastructures.CombinedMultiDict` that combines
:attr:`args` and :attr:`form`.'

@cached_property
def values(self):

    args = []
    for d in (self.args, self.form):
        if (not isinstance(d, MultiDict)):
            d = MultiDict(d)
        args.append(d)
    return CombinedMultiDict(args)
