private function addCustomerDetails($quote, $email)
    {
        $quote->setCustomerEmail($email);
        if (!$quote->getCustomerId()) {
            $quote->setCustomerId(null);
            $quote->setCheckoutMethod('guest');
            $quote->setCustomerIsGuest(true);
            $quote->setCustomerGroupId(GroupInterface::NOT_LOGGED_IN_ID);
        }
    }