Contao\Messages::maintenanceCheck PHP Method

    public function maintenanceCheck()
    {
        $this->import('BackendUser', 'User');
        if (!$this->User->hasAccess('maintenance', 'modules')) {
            return '';
        }
        try {
            if (\System::getContainer()->get('lexik_maintenance.driver.factory')->getDriver()->isExists()) {
                return '<p class="tl_error">' . $GLOBALS['TL_LANG']['MSC']['maintenanceEnabled'] . '</p>';
            }
        } catch (\Exception $e) {
            // ignore
        }
        return '';
    }