core-bundle/src/Resources/contao/pages/PageError403.php
public function getResponse($objRootPage=null)
	{
		/** @var PageModel $objPage */
		global $objPage;

		$obj403 = $this->prepare($objRootPage);
		$objPage = $obj403->loadDetails();

		/** @var PageRegular $objHandler */
		$objHandler = new $GLOBALS['TL_PTY']['regular']();

		return $objHandler->getResponse($objPage)->setStatusCode(403);
	}
public function getResponse($objRootPage=null)
	{
		/** @var PageModel $objPage */
		global $objPage;

		$obj403 = $this->prepare($objRootPage);
		$objPage = $obj403->loadDetails();

		/** @var PageRegular $objHandler */
		$objHandler = new $GLOBALS['TL_PTY']['regular']();

		return $objHandler->getResponse($objPage)->setStatusCode(403);
	}
Return a response object

@param PageModel|integer $objRootPage

@return Response