public static function getAllProjectVersions(CNabuProject $nb_project)
    {
        $nb_project_id = nb_getMixedValue($nb_project, 'nb_project_id');
        if (is_numeric($nb_project_id)) {
            $retval = forward_static_call(
            array(get_called_class(), 'buildObjectListFromSQL'),
                'nb_project_version_id',
                'select * '
                . 'from nb_project_version '
               . 'where nb_project_id=%project_id$d',
                array(
                    'project_id' => $nb_project_id
                ),
                $nb_project
            );
        } else {
            $retval = new CNabuProjectVersionList();
        }
        
        return $retval;
    }