Importing problem 
- `transformers` version: 4.5.1
- It just cannot import the version., . cannot import name 'PegasusTokenizer' from 'transformers', python 3.8
try the newest version 4.6.0.dev0

![image](https://user-images.githubusercontent.com/54096137/116375420-d7b16580-a841-11eb-8d0e-e562d5dfb263.png)

<|||||>Could you install `sentencepiece` and try again? The `PegasusTokenizer` is based on the `sentencepiece` library.<|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/master/CONTRIBUTING.md) are likely to be ignored.<|||||>Iam also facing the same issue