code: def BatchConvert(self, metadata_value_pairs, token=None):
      
      if data_store.RelationalDBEnabled():
        result_generator = self._BatchConvertRelational(metadata_value_pairs)
      else:
        result_generator = self._BatchConvertLegacy(
            metadata_value_pairs, token=token)
  
      for r in result_generator:
        yield r
docs: Converts a batch of StatEntry value to ExportedFile values at once.
  
      Args:
        metadata_value_pairs: a list or a generator of tuples (metadata, value),
          where metadata is ExportedMetadata to be used for conversion and value
          is a StatEntry to be converted.
        token: Security token:
  
      Yields:
        Resulting ExportedFile values. Empty list is a valid result and means that
        conversion wasn't possible.