public function exportSurveyReturnCode($recordId, $form, $event = null, $repeatInstance = null)
    {
        $data = array(
                'token' => $this->apiToken,
                'content' => 'surveyReturnCode',
                'returnFormat' => 'json'
        );
        
        #----------------------------------------------
        # Process arguments
        #----------------------------------------------
        $data['record']          = $this->processRecordIdArgument($recordId, $required = true);
        $data['instrument']      = $this->ProcessFormArgument($form, $required = true);
        $data['event']           = $this->ProcessEventArgument($event);
        $data['repeat_instance'] = $this->ProcessRepeatInstanceArgument($repeatInstance);
        
        $surveyReturnCode = $this->connection->callWithArray($data);
        $surveyReturnCode = $this->processExportResult($surveyReturnCode, 'string');
        
        return $surveyReturnCode;
    }