Text_Classification_Sentiment_Analysis tutorial is broken
Could you please try with `BRANCH='main'` in the first cell of the notebook. @ekmb Tried `BRANCH='main'` but still getting the same error I forgot to restart the kernel when trying `BRANCH='main'`. So I restarted the kernel and tried `from nemo.collections import nlp as nemo_nlp` and the original `ModuleNotFoundError: No module named 'transformers.tokenization_bert'` has gone away but there is a different `ModuleNotFoundError: No module named 'webdataset'`: 
![image](https://user-images.githubusercontent.com/73861554/102415438-01fa3900-3fad-11eb-99d9-5a85397dfa81.png)
 Could you please restart the kernel and run this one:

BRANCH = 'main'
!python -m pip install git+https://github.com/NVIDIA/NeMo.git@$BRANCH#egg=nemo_toolkit[all]


 Tried it and it seems like it's fixed now. Not getting any more errors. There are two APEX warnings though:

![image](https://user-images.githubusercontent.com/73861554/102417301-43401800-3fb0-11eb-98f1-fb15688cbad5.png)

 @kshitizgupta21 the warnings are OK (Colab doesn't have APEX). 
Getting `ModuleNotFoundError: No module named 'transformers.tokenization_bert'` in Text_Classification_Sentiment_Analysis.ipynb notebook:

![image](https://user-images.githubusercontent.com/73861554/102413997-a5961a00-3faa-11eb-8a16-432fccb43eca.png)



