//           can be null. The names used for function inputs are normalized
//           names of the operations (usually placeholders) pointed to by
//           `inputs`. These operation names should start with a letter.
//           Normalization will convert all letters to lowercase and
//           non-alphanumeric characters to '_' to make resulting names match

  /// be set to the reason why one entry couldn't be removed and the proper
  /// count must be updated. If the deletion is unsuccessful because the
  /// traversal couldn't start, `*undeleted_files` must be set to 0 and
  /// `*undeleted_dirs` must be set to 1.
  ///
  /// TODO(b/139060984): After all filesystems are converted, consider
  /// invariant about `*undeleted_files` and `*undeleted_dirs`.