Set TermsOfPayment depending on payment method

functions.php

<?
/**
* @snippet WooCommerce - Fortnox plugin by Redlight Media - Set TermsOfPayment depending on payment method via functions.php
* @author Redlight Media AB / Christopher Hedqvist
* @compatible WooCommerce 3.2.5
*/
function redlight_fortnox_payment_method_TermsOfPayment($orderData, $order_id) {
    $order = wc_get_order($order_id);
    $order_payment_method = $order->get_payment_method();
    switch( $order_payment_method ) {
        case 'klarna':
        case 'klarna_account':
        case 'klarna_special_campaign':
        case 'klarna_invoice':
        case 'klarna_part_payment':
        case 'klarna_checkout':
            $orderData['Order']['TermsOfPayment'] = 'KLARNA' ;
            break;
        case 'dibs':
        case 'dibs_invoice':
        case 'dibs_masterpass':
        case 'dibs_mobilepay':
            $orderData['Order']['TermsOfPayment'] = 'DIBS' ;
            break;
        case 'redlight_swish':
        case 'redlight_swish-ecommerce':
            $orderData['Order']['TermsOfPayment'] = 'SWISH' ;
            break;
        default:
            $orderData['Order']['TermsOfPayment'] = '' ;
    }
    
    return $orderData;
}
add_filter('obj_fortnox_order_data', 'redlight_fortnox_payment_method_TermsOfPayment', 10, 2 );