def WaymoValSpec(params):
  """Validation set.

  Validation contains no overlapping run segments with training.

  Args:
    params: A Waymo open dataset input params.

  Returns:
    An updated Waymo open dataset params with the validation spec.
  """
  p = params.Copy()
  p.file_datasource.base_datasource.file_pattern = 'valid.tfr-*-of-01000'
  p.num_samples = 40077
  return p