public function warning($mes, $alert = true) {
        \AsyncWeb\Storage\Log::log("MessagesWarning", "Bola zobrazena varovacia hlaska: " . addslashes($mes), ML__LOW_PRIORITY);
        $this->warn.= '<div class="error alert alert-warning">' . $mes . '</div>' . "\n";
        \AsyncWeb\Storage\Session::set($this->conf_ses_save_err, $this->warn);
        if ($alert) {
            $this->addAlert($mes);
        }
    }