Convert a ProgramVariable instance to a DDGViewItem object.

        :param ProgramVariable prog_var: The ProgramVariable object to convert.
        :return:                         The converted DDGViewItem object.
        :rtype:                          DDGViewItem

def _to_viewitem(self, prog_var):
        """
        Convert a ProgramVariable instance to a DDGViewItem object.

        :param ProgramVariable prog_var: The ProgramVariable object to convert.
        :return:                         The converted DDGViewItem object.
        :rtype:                          DDGViewItem
        """

        return DDGViewItem(self._ddg, prog_var, simplified=self._simplified)