protected function callStepAndCheckForException($stepName, $args = array())
    {
        try {
            $response = call_user_func_array(array($this->exampleClass, $stepName), $args);
        } catch (OffAmazonPaymentsService_Exception $ex) {
            $this->printExceptionToCLI($ex, $stepName);
            throw $ex;
        }

        return $response;
    }