Cake\Network\Session::_overwrite PHP Метод

    protected function _overwrite(&$old, $new)
    {
        if (!empty($old)) {
            foreach ($old as $key => $var) {
                if (!isset($new[$key])) {
                    unset($old[$key]);
                }
            }
        }
        foreach ($new as $key => $var) {
            $old[$key] = $var;
        }
    }