public static function isProcessing( eZContentObjectVersion $versionObject )
    {
        $count = parent::count(
            self::definition(),
            array(
                'ezcontentobject_version_id' => $versionObject->attribute( 'id' ),
                // 'status' => self::STATUS_WORKING // not used yet
            )
        );
        return ( $count != 0 );
    }