//   must be either listed in `inputs` or must come from another node in
//   the body. In particular, it is an error to have a control edge going from
//   a node outside of the body into a node in the body. This applies to control
//   edges going from nodes referenced in `inputs` to nodes in the body when
//   the former nodes are not in the body (automatically skipped or not
//   included in explicitly specified body).

  ///   * Must set `status` to `TF_FAILED_PRECONDITION` if `path` is invalid or
  ///     if it exists but is not a directory.
  ///   * Might use any other error value for `status` to signal other errors.
  ///
  /// NOTE: The requirements specify that `TF_ALREADY_EXISTS` is not returned if
  /// directory exists. Similarly, `TF_NOT_FOUND` is not be returned, as the
  /// missing directory entry and all its descendants will be created by the