anchor.diff:  
     /// Creates a new XmlParentException.
     XmlParentException(String message) : super(message);
  +
  +  @override
  +  String toString() => 'XmlParentException: $message';
   }
   
   /// Exception thrown when the end tag does not match the open tag.
  
positive.code:   int? get offset => position;
  
    @override
    String toString() => '${super.toString()} at $line:$column';
  }
  
  /// Exception thrown when an unsupported node type is used.
  
negative.code: 
    /// Creates a new XmlNodeTypeException.
    XmlNodeTypeException(String message) : super(message);
  
    @override
    String toString() => 'XmlNodeTypeException: $message';
  }
  
  /// Exception thrown when the parent relationship between nodes is invalid.
  