Cart/EventListener/CartListener.php
protected function updateExpiresAt(CartInterface $cart)
    {
        $date = new \DateTime();
        $date->modify($this->expirationDelay);
        $cart->setExpiresAt($date);

        return true;
    }
protected function updateExpiresAt(CartInterface $cart)
    {
        $date = new \DateTime();
        $date->modify($this->expirationDelay);
        $cart->setExpiresAt($date);

        return true;
    }
Updates the cart expiration date.

@param CartInterface $cart

@return bool