def get_all_label_values(dataset_info):
  """Retrieves possible values for modeled labels from a `Seq2LabelDatasetInfo`.

  Args:
    dataset_info: a `Seq2LabelDatasetInfo` message.

  Returns:
    A dictionary mapping each label name to a tuple of its permissible values.
  """
  return {
      label_info.name: tuple(label_info.values)
      for label_info in dataset_info.labels
  }