code: public function getEligibleShippingServices($request)
      {
          if (!($request instanceof MWSMerchantFulfillmentService_Model_GetEligibleShippingServicesRequest)) {
              require_once (dirname(__FILE__) . '/Model/GetEligibleShippingServicesRequest.php');
              $request = new MWSMerchantFulfillmentService_Model_GetEligibleShippingServicesRequest($request);
          }
          $parameters = $request->toQueryParameterArray();
          $parameters['Action'] = 'GetEligibleShippingServices';
          $httpResponse = $this->_invoke($parameters);
  
          require_once (dirname(__FILE__) . '/Model/GetEligibleShippingServicesResponse.php');
          $response = MWSMerchantFulfillmentService_Model_GetEligibleShippingServicesResponse::fromXML($httpResponse['ResponseBody']);
          $response->setResponseHeaderMetadata($httpResponse['ResponseHeaderMetadata']);
          return $response;
      }
docs: Get Eligible Shipping Services
  Gets a list of eligible shipping services for the shipment information specified.  The ShippingServiceId or
  ShippingServiceOfferingId can be used in CreateShipment to specify the shipping service or the specific offer
  respectively.  A list of carriers that are temporarily unavailable is also returned.
  
  @param mixed $request array of parameters for MWSMerchantFulfillmentService_Model_GetEligibleShippingServices request or MWSMerchantFulfillmentService_Model_GetEligibleShippingServices object itself
  @see MWSMerchantFulfillmentService_Model_GetEligibleShippingServicesRequest
  @return MWSMerchantFulfillmentService_Model_GetEligibleShippingServicesResponse
  
  @throws MWSMerchantFulfillmentService_Exception