public function addRow($rows = null) {
        if( ! is_array($rows) ) {
            $rows = func_get_args();
        }
        $row = new TableRow;
        foreach( $rows as $arg ) {
            $cell = new TableCell;
            $cell->addChild( $arg );
            $row->addChild( $cell );
        }
        $this->addChild($row);
        return $row;
    }