Verplichte checkbox toevoegen in WooCommerce + notificatie indien niet ingevuld

gistfile1.txt

/**
 * Add WooCommerce Checkbox checkout
 */
add_action( 'woocommerce_review_order_before_submit', 'woofers_add_checkout_checkbox', 10 );
function woofers_add_checkout_checkbox() {

    woocommerce_form_field( 'checkout-checkbox', array( // CSS ID
       'type'          => 'checkbox',
       'class'         => array('form-row mycheckbox'), // CSS Class
       'label_class'   => array('woocommerce-form__label woocommerce-form__label-for-checkbox checkbox'),
       'input_class'   => array('woocommerce-form__input woocommerce-form__input-checkbox input-checkbox'),
       'required'      => true, // Mandatory or Optional
       'label'         => 'Yes, I agree with <a href="/return-policy/" target="_blank" rel="noopener"><u>return policy</u>.</a><br/>Sales, under € 30 items and accessories are non-returnable. All other items can be send back within 14 days in return for a gift certificate.', // Label and Link
    ));
}

add_action( 'woocommerce_checkout_process', 'bt_add_checkout_checkbox_warning' );
/**
 * Alert if checkbox not checked
 */
function bt_add_checkout_checkbox_warning() {
    if ( ! (int) isset( $_POST['checkout-checkbox'] ) ) {
        wc_add_notice( __( 'Please agree with our return policy to order' ), 'error' );
    }
}