Dataset Viewer issue for indonesian-nlp/librivox-indonesia
### Link

https://huggingface.co/datasets/indonesian-nlp/librivox-indonesia

### Description

I created a new speech dataset https://huggingface.co/datasets/indonesian-nlp/librivox-indonesia, but the dataset preview doesn't work with following error message:
```
Server error
Status code:   400
Exception:     TypeError
Message:       unsupported operand type(s) for +: 'NoneType' and 'str'
```
Please help, I am not sure what the problem here is. Thanks a lot.

### Owner

Yes