code: def appendRecords(self, records, progressCB=None):
      
  
      for record in records:
        self.appendRecord(record)
        if progressCB is not None:
          progressCB()
docs: Saves multiple records in the underlying storage.
  
      :param records: array of records as in
                      :meth:`~.FileRecordStream.appendRecord`
      :param progressCB: (function) callback to report progress