Reference to how to prevent access to a page for guests in Magento 2

MagentoController.php

<?php

use Magento\Customer\Model\Session as CustomerSession;
use Magento\Framework\App\Action\Action;
use Magento\Framework\App\Action\Context;
use Magento\Framework\App\RequestInterface;
use Magento\Framework\Controller\ResultFactory;

class Index extends Action
{
    /**
     * @var CustomerSession
     */
    protected $customerSession;

    /**
     * @param CustomerSession $customerSession
     * @param Context         $context
     */
    public function __construct(CustomerSession $customerSession, Context $context)
    {
        parent::__construct($context);
        $this->customerSession = $customerSession;
    }

    /**
     * {@inheritDoc}
     * @throws \InvalidArgumentException
     */
    public function execute()
    {
        /** @var \Magento\Framework\View\Result\Page $resultPage */
        return $this->resultFactory->create(ResultFactory::TYPE_PAGE);=
    }

    /**
     * Check customer authentication
     *
     * @param RequestInterface $request
     *
     * @return \Magento\Framework\App\ResponseInterface
     * @throws \Magento\Framework\Exception\NotFoundException
     */
    public function dispatch(RequestInterface $request)
    {
        if (!$this->customerSession->authenticate()) {
            $this->_actionFlag->set('', 'no-dispatch', true);
        }

        return parent::dispatch($request);
    }

}