def _add_meta_value_to_xml_doc(self, doc, parent, obj):
        """Values in the meta element dict are converted to a BadgerFish-style
            encoding (see _convert_hbf_meta_val_for_xml), so regardless of input_format,
            we treat them as if they were BadgerFish.
        """
        return self._add_subtree_to_xml_doc(doc,
                                            parent,
                                            subtree=obj,
                                            key='meta',
                                            key_order=None)