Send new order email to additional reciepient wher coupon applied

functions.php

<?php

add_filter( 'woocommerce_email_recipient_new_order', 'studiowp_woocommerce_email_recipient_new_order', 10, 2 );
function studiowp_woocommerce_email_recipient_new_order( $recipient, $order ) {
    $coupon_code = 'XXXXXXXX';
    $add_recipient = 'email@domain.com';
    if ( in_array( strtolower( $coupon_code ), $order->get_used_coupons() ) ) {
        $recipient .= ',' . $add_recipient;
    }
    return $recipient;
}

Exploration for this code https://en.studiowp.net/send-new-order-email-additional-address-coupon-applied/