* shipping method to be added.
* @return list of {@see FlatRateShipping}, {@see MerchantCalculatedShipping},
* {@see Pickup}
*/
private ShippingMethods addShippingMethod(Object shippingMethod) {
ShippingMethods methods
= _objectFact.createMerchantCheckoutFlowSupportShippingMethods();
List methodList
= methods.getFlatRateShippingOrMerchantCalculatedShippingOrPickup();
methodList.add(shippingMethod);
return methods;
}