YayMail: WooCommerce Sequential Order Shortcode

function zf_sequential_order_yaymail_shortcode(  $shortcode_list, $yaymail_informations, $args = array() ) {
	// Real Order Lookup
	if (isset ($args['order'])) {
		$order = $args['order'];
		$order_id = $order->get_order_number();
		return $order_id;
	}
	
	// YayMail Preview
	return 'PRE_XXXX';
}

add_filter(
	'yaymail_customs_shortcode',
	function( $shortcode_list, $yaymail_informations, $args = array() ) {
			$shortcode_list['[yaymail_custom_shortcode_sequential_order_number]']  = zf_sequential_order_yaymail_shortcode($shortcode_list, $yaymail_informations, $args);
		return $shortcode_list;
	},
	10,
	3
);