ImportError: cannot import name 'AdamW' from 'transformers' (unknown location)
### Steps to reproduce -  
```python3
!pip install --quiet transformers==4.5.0
!pip install --quiet pytorch-lightning==1.2.7

from transformers import (
     AdamW,
     T5ForConditionalGeneration,
     T5TokenizerFast as T5Tokenizer
 )
```

Throws error -
```bash
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
/tmp/ipykernel_3065/106495151.py in <module>
---> 22 from transformers import (
     23      AdamW,
     24      T5ForConditionalGeneration,

ImportError: cannot import name 'AdamW' from 'transformers' (unknown location)

```
Hi, I just tried this and was able to import `AdamW`, make sure you have `torch` installed.<|||||>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.<|||||>I am also facing this problem when running the [code](https://colab.research.google.com/drive/1IDwie_Te_2GntHay_zZ-oPvriNsacQ8d#) for pretraining wav2vec2.

edit: found the solution: use transformers==4.20.0<|||||>the version of the torch must be >=1.2.0, "AdamW" optim can be used