if ($tax_group_id == null)
$tax_group_id = $this->tax_group_id;
$taxes = get_tax_for_items($items, $prices, $shipping_cost, $tax_group_id,
if ($tax_group_id == null)
$tax_group_id = $this->tax_group_id;
$taxes = get_tax_for_items($items, $prices, $shipping_cost, $tax_group_id,