code: def _CreateOutputFileHandles(self, output_type):
      
      gzip_filehandle_parent = tempfile.NamedTemporaryFile(suffix=output_type)
      gzip_filehandle = gzip.GzipFile(gzip_filehandle_parent.name, "wb",
                                      self.GZIP_COMPRESSION_LEVEL,
                                      gzip_filehandle_parent)
      self.temp_output_trackers[output_type] = TempOutputTracker(
          output_type=output_type,
          gzip_filehandle=gzip_filehandle,
          gzip_filehandle_parent=gzip_filehandle_parent)
      return self.temp_output_trackers[output_type]
docs: Creates a new gzipped output tempfile for the output type.
  
      We write to JSON data to gzip_filehandle to get compressed data. We hold a
      reference to the original filehandle (gzip_filehandle_parent) so we can pass
      the gzip data to bigquery.
  
      Args:
        output_type: string of export type to be used in filename. e.g.
          ExportedFile
  
      Returns:
        A TempOutputTracker object