 Error tokenizer = AutoTokenizer.from_pretrained("vinai/phobert-base")
I run pretrain PhoBERT error .
ValueError                                Traceback (most recent call last)
<ipython-input-75-d17717702336> in <module>()
      3 
      4 phobert = AutoModel.from_pretrained("vinai/phobert-base")
----> 5 tokenizer = AutoTokenizer.from_pretrained("vinai/phobert-base")
      6 
      7 # INPUT TEXT MUST BE ALREADY WORD-SEGMENTED!

/usr/local/lib/python3.6/dist-packages/transformers/models/auto/tokenization_auto.py in from_pretrained(cls, pretrained_model_name_or_path, *inputs, **kwargs)
    323             if tokenizer_class is None:
    324                 raise ValueError(
--> 325                     "Tokenizer class {} does not exist or is not currently imported.".format(tokenizer_class_candidate)
    326                 )
    327             return tokenizer_class.from_pretrained(pretrained_model_name_or_path, *inputs, **kwargs)

ValueError: **Tokenizer class PhobertTokenizerFast does not exist or is not currently imported.**
Hey @trungtruc123, 

can you try upgrading your transformer version?
The following code snippet (as stated on the model card: https://github.com/VinAIResearch/PhoBERT) works perfectly fine for me.

```python
import torch
from transformers import AutoModel, AutoTokenizer

phobert = AutoModel.from_pretrained("vinai/phobert-base")

# For transformers v4.x+: 
tokenizer = AutoTokenizer.from_pretrained("vinai/phobert-base", use_fast=False)
```

Version:
- `transformers` version: 4.1.0.dev0
- Platform: Linux-5.4.0-1030-gcp-x86_64-with-glibc2.10
- Python version: 3.8.5
- PyTorch version (GPU?): 1.8.0.dev20201117 (True)
- Tensorflow version (GPU?): 2.3.1 (False)
- Using GPU in script?: <fill in>
- Using distributed or parallel set-up in script?: <fill in>


It should also work with transformers 4.0.0.<|||||>This issue has been automatically marked as stale and been closed because it has not had recent activity. Thank you for your contributions.

If you think this still needs to be addressed please comment on this thread.