anchor.diff:      _performEdit(edit, path, expected);
     }
   
  -  /// Changes the contents of the list at [path] by removing [deleteCount] items
  -  /// at [index], and inserting [values] in-place. Returns the elements that
  -  /// are deleted.
  +  /// Changes the contents of the list at [path] by removing [deleteCount]
  +  /// items at [index], and inserting [values] in-place. Returns the elements
  +  /// that are deleted.
     ///
     /// [index] and [deleteCount] must be non-negative and [index] + [deleteCount]
     /// must be no greater than the list's length.
     ///
  -  /// Throws a [ArgumentError] if the element at the given path is not a [YamlList]
  -  /// or if the path is invalid.
  +  /// Throws a [ArgumentError] if the element at the given path is not a
  +  /// [YamlList] or if the path is invalid.
     ///
     /// **Example:**
     /// ```dart
  
positive.code: /// such a situation should be extremely rare, and should only occur with
  /// degenerate formatting.
  ///
  /// Most modification methods require the user to pass in an [Iterable<Object>]
  /// path that holds the keys/indices to navigate to the element.
  ///
  /// **Example:**
  
negative.code:   ///
    /// Convenience function to ensure that a [YamlList] is returned.
    ///
    /// Throws [ArgumentError] if the element at the given path is not a
    /// [YamlList] or if the path is invalid. If [checkAlias] is `true`, and an
    /// aliased node is encountered along [path], an [AliasError] will be thrown.
    YamlList _traverseToList(Iterable<Object> path, {bool checkAlias = false}) {
      ArgumentError.checkNotNull(path, 'path');
      ArgumentError.checkNotNull(checkAlias, 'checkAlias');
  