anchor.diff:    bool get hasGetter => _variable.getter != null;
   
     bool get hasSetter => _variable.setter != null;
  +
  +  // TODO: check if this works for libraries and classes
  +  @override
  +  String get _href => throw 'Not implemented yet';
   }
   
   class Parameter extends ModelElement {
  
positive.code:     }).toList();
    }
  
    String get _href => '${library.name}/$name.html';
  }
  
  
negative.code:     }
      return getTypes().where(isExceptionOrError).toList();
    }
  
    @override
    String get _href => '$name/index.html';
  }
  
  class Class extends ModelElement {
  