问题 I use the code below to add a VAT field in woocommerce address. It's works but, it throws this error: Notice: billing_vat est appelée de la mauvaise manière. Order properties should not be accessed directly. Backtrace: require('wp-admin/edit-form-advanced.php'), do_meta_boxes, WC_Meta_Box_Order_Data::output, WC_Order->get_formatted_billing_address, apply_filters('woocommerce_order_formatted_billing_address'), WP_Hook->apply_filters, custom_add_vat_formatted_billing_address, WC_Abstract_Legacy