anchor.diff:    if (data == null) {
       return null;
     } else if (data is List) {
  -    return data.map(unmarshalInt64Data).toList();
  +    return new ObservableList.from(data.map(unmarshalInt64Data));
     } else if (data is String) {
       return Int64.parseInt(data);
     } else {
  
positive.code:   if (data == null) {
      return null;
    } else if (data is List) {
      return data.map(marshalDataToString).toList();
    } else {
      return data.toString();
    }
  
negative.code:   if (data == null) {
      return null;
    } else if (data is List) {
      return new ObservableList.from(data.map((v) => handleEntityData(v, marshaller, handler, marshal)));
    } else {
      return handler(marshaller, data, marshal);
    }
  