public function getItemData(RunnerServiceContext $context, $itemRef)
    {
        if ($context instanceof QtiRunnerServiceContext) {

            return $this->loadItemData($itemRef, QtiJsonItemCompiler::ITEM_FILE_NAME);

        } else {
            throw new \common_exception_InvalidArgumentType(
                'QtiRunnerService',
                'getItemData',
                0,
                'oat\taoQtiTest\models\runner\QtiRunnerServiceContext',
                $context
            );
        }
    }