public function verifyConfiguration()
    {
        if (($this->strategy === CoreConstants::EXPORT_STRATEGY) && !empty($this->strategy)) {
            if (is_null($this->exportDir)) {
                throw new SdkException("Invalid value for exportDirectory property. It can not be null with 'export' strategy. ");
            }
          //clear file cache
          clearstatcache();
            if (!file_exists($this->exportDir)) {
                throw new SdkException("Directory ({$this->exportDir}) doesn't exist.");
            }

            if (!is_dir($this->exportDir)) {
                throw new SdkException("Path ({$this->exportDir}) isn't a valid directory");
            }

            if (!is_writable($this->exportDir)) {
                throw new SdkException("Directory ({$this->exportDir}) isn't writable");
            }
        }
    }