docs: def dataset_format_to_extension(ds_format):
      """
      Get the preferred Dataset format extension
  
      :param str ds_format: Format of the Dataset (expected to be one of `csv` or `xml`)
      :rtype: str
      """
      try:
          return DATASET_FORMATS[ds_format]
      except KeyError:
          raise ValueError(
              "dataset_format is expected to be one of %s. '%s' is not valid"
              % (", ".join(DATASET_FORMATS.keys()), ds_format)
          )