code: public function run()
  	{
  		$objTemplate = new BackendTemplate('be_maintenance_mode');
  		$objTemplate->action = ampersand(Environment::get('request'));
  		$objTemplate->headline = $GLOBALS['TL_LANG']['tl_maintenance']['maintenanceMode'];
  		$objTemplate->isActive = $this->isActive();
  
  		try
  		{
  			$driver = System::getContainer()->get('lexik_maintenance.driver.factory')->getDriver();
  			$isLocked = $driver->isExists();
  		}
  		catch (\Exception $e)
  		{
  			return '';
  		}
  
  		// Toggle the maintenance mode
  		if (Input::post('FORM_SUBMIT') == 'tl_maintenance_mode')
  		{
  			if ($isLocked)
  			{
  				$driver->unlock();
  			}
  			else
  			{
  				$driver->lock();
  			}
  
  			$this->reload();
  		}
  
  		if ($isLocked)
  		{
  			$objTemplate->class= 'tl_error';
  			$objTemplate->explain = $GLOBALS['TL_LANG']['MSC']['maintenanceEnabled'];
  			$objTemplate->submit = $GLOBALS['TL_LANG']['MSC']['disable'];
  		}
  		else
  		{
  			$objTemplate->class= 'tl_info';
  			$objTemplate->submit = $GLOBALS['TL_LANG']['MSC']['enable'];
  		}
  
  		return $objTemplate->parse();
  	}
docs: Generate the module
  
  @return string