woocommerce_upsells_order │ filter-hook │ WC 1.0

Usage

add_filter( 'woocommerce_upsells_order', 'wp_kama_woocommerce_upsells_order_filter' );

/**
 * Function for `woocommerce_upsells_order` filter-hook.
 * 
 * @param  $args[order] 
 *
 * @return 
 */
function wp_kama_woocommerce_upsells_order_filter( $args[order] ){

	// filter...
	return $args[order];
}

$args[order]

-

Where the hook is called

$order   = apply_filters( 'woocommerce_upsells_order', isset( $args['order'] ) ? $args['order'] : $order );

Where the hook is used in WooCommerce