/**
  * Finalizes the files stored in $this->files.
  * If it has 1 file, it will return that file, if it has more, it will return a zip containing all the files, named as the first file in the array.
  * @return File with download headers
  */
 public function finalizeFiles()
 {
     parent::finalizeFiles();
     if (!$this->batch) {
         $this->_session->rowNumber = 0;
     }
 }