code: public function estimateTransportRequest($request)
      {
          if (!($request instanceof FBAInboundServiceMWS_Model_EstimateTransportInputRequest)) {
              $request = new FBAInboundServiceMWS_Model_EstimateTransportInputRequest($request);
          }
          $parameters = $request->toQueryParameterArray();
          $parameters['Action'] = 'EstimateTransportRequest';
          $httpResponse = $this->_invoke($parameters);
  
          $response = FBAInboundServiceMWS_Model_EstimateTransportRequestResponse::fromXML($httpResponse['ResponseBody']);
          $response->setResponseHeaderMetadata($httpResponse['ResponseHeaderMetadata']);
          return $response;
      }
docs: Estimate Transport Request
  Initiates the process for requesting an estimated shipping cost based-on the shipment
  for which the request is being made, whether or not the carrier shipment is partnered/non-partnered
  and the carrier type.
  
  @param mixed $request array of parameters for FBAInboundServiceMWS_Model_EstimateTransportRequest request or FBAInboundServiceMWS_Model_EstimateTransportRequest object itself
  @see FBAInboundServiceMWS_Model_EstimateTransportInputRequest
  @return FBAInboundServiceMWS_Model_EstimateTransportRequestResponse
  
  @throws FBAInboundServiceMWS_Exception