ValueError: Tokenizer class `NllbTokenizer` does not exist or is not currently imported when using NLLB (On Paperspace)
### System Info

Hello,

When i use the code below
```py
...
 tokenizer = AutoTokenizer.from_pretrained("facebook/nllb-200-distilled-600M")
...
```

Models : `nllb-distilled-600M`

I got an error in my notebook instance (on `paperspace`) and I thought the problem was with the version of huggingface `(4.26.0.dev0)` even if I was on the right one it still doesn't work.

🤗
 

### Who can help?

_No response_

### Information

- [X] The official example scripts
- [ ] My own modified scripts

### Tasks

- [ ] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [ ] My own task or dataset (give details below)

### Reproduction

```py
...
def load_models():
    # build model and tokenizer
    model_name_dict = {'nllb-distilled-600M': 'facebook/nllb-200-distilled-600M',
                  #'nllb-1.3B': 'facebook/nllb-200-1.3B',
                  #'nllb-distilled-1.3B': 'facebook/nllb-200-distilled-1.3B',
                  #'nllb-3.3B': 'facebook/nllb-200-3.3B',
                  }

    model_dict = {}

    for call_name, real_name in model_name_dict.items():
        print('\tLoading model: %s' % call_name)
        model = AutoModelForSeq2SeqLM.from_pretrained(real_name)
        tokenizer = AutoTokenizer.from_pretrained(real_name)
        model_dict[call_name+'_model'] = model
        model_dict[call_name+'_tokenizer'] = tokenizer

    return model_dict
...
```

### Expected behavior

See my model working as except on the Gradio space
Bug resolved ! 
I relaunch my instance many times and run this command `!pip3 install git+https://github.com/huggingface/transformers.git`<|||||>I have the same problem. help!!!