ElggMetadata::enable PHP Method

    public function enable()
    {
        $success = _elgg_set_metastring_based_object_enabled_by_id($this->id, 'yes', 'metadata');
        if ($success) {
            $this->enabled = 'yes';
            _elgg_services()->metadataCache->clear($this->entity_guid);
        }
        return $success;
    }