def uniquetwig(self, ps=None):
        """
        see also :meth:`twig`

        Determine the shortest (more-or-less) twig which will point
        to this single Parameter in a given parent :class:`ParameterSet`

        :parameter ps: :class:`ParameterSet` in which the returned
            uniquetwig will point to this Parameter.  If not provided
            or None this will default to the parent :class:`phoebe.frontend.bundle.Bundle`,
            if available.
        :return: uniquetwig
        :rtype: str
        """
        if ps is None:
            ps = self._bundle

        if ps is None:
            return self.twig
        return ps._uniquetwig(self.twig)