if ($links = $this->get_item_tags(SIMPLEPIE_NAMESPACE_RSS_20, 'guid'))
            {
                if (!isset($links[0]['attribs']['']['isPermaLink']) || strtolower(trim($links[0]['attribs']['']['isPermaLink'])) === 'true')
                {
                    $this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], SIMPLEPIE_CONSTRUCT_IRI, $this->get_base($links[0]));