def _ParseClustering(clustering_fields=None):
  """Parses clustering from the arguments.

  Args:
    clustering_fields: Comma-separated field names.

  Returns:
    Clustering if any of the arguments is not None, otherwise None. Special
    case if clustering_fields is passed in as an empty string instead of None,
    in which case we'll return {}, to support the scenario where user wants to
    update a table and remove the clustering spec.
  """

  if clustering_fields == '':  # pylint: disable=g-explicit-bool-comparison
    return {}
  elif clustering_fields is not None:
    return {'fields': clustering_fields.split(',')}
  else:
    return None