Usage Of Session Handler Class

Session Usage

$session = new SecureSessionHandler('cheese');

ini_set('session.save_handler', 'files');
session_set_save_handler($session, true);
session_save_path(__DIR__ . '/sessions');

$session->start();

if ( ! $session->isValid(5)) {
    $session->destroy();
}

$session->put('hello.world', 'bonjour');

echo $session->get('hello.world'); // bonjour

How do you reuse the $session object across pages?
i.e. what if I create a new session in a login.php page, then I redirect to secure.php and want to check whether the session is still valid?

call $session->isValid();