ModuleNotFoundError: No module named 'transformers.tokenization_bert' 
Hello!

I am running 00_NeMo_Primer.

I was running this cell
```
import nemo.collections.asr as nemo_asr
import nemo.collections.tts as nemo_tts
import nemo.collections.nlp as nemo_nlp
```

And got the following error
```
[NeMo W 2022-02-17 15:16:17 experimental:27] Module <class 'nemo.collections.asr.losses.ctc.CTCLoss'> is experimental, not ready for production and is not fully supported. Use at your own risk.
[NeMo W 2022-02-17 15:16:18 experimental:27] Module <class 'nemo.collections.tts.losses.glow_tts_loss.GlowTTSLoss'> is experimental, not ready for production and is not fully supported. Use at your own risk.
[NeMo W 2022-02-17 15:16:18 experimental:27] Module <class 'nemo.collections.tts.modules.glow_tts.TextEncoder'> is experimental, not ready for production and is not fully supported. Use at your own risk.
[NeMo W 2022-02-17 15:16:18 experimental:27] Module <class 'nemo.collections.tts.modules.glow_tts.FlowSpecDecoder'> is experimental, not ready for production and is not fully supported. Use at your own risk.
---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
/var/folders/6p/q3vy70_j01x7j6tw4kzc_dy00000gp/T/ipykernel_5722/4141817862.py in <module>
      1 import nemo.collections.asr as nemo_asr
      2 import nemo.collections.tts as nemo_tts
----> 3 import nemo.collections.nlp as nemo_nlp

~/opt/anaconda3/lib/python3.9/site-packages/nemo/collections/nlp/__init__.py in <module>
     13 # limitations under the License.
     14 
---> 15 from nemo.collections.nlp import data, models, modules
     16 from nemo.package_info import __version__
     17 

~/opt/anaconda3/lib/python3.9/site-packages/nemo/collections/nlp/data/__init__.py in <module>
     19     BertPretrainingPreprocessedDataloader,
     20 )
---> 21 from nemo.collections.nlp.data.question_answering_squad.qa_dataset import SquadDataset
     22 from nemo.collections.nlp.data.token_classification.token_classification_dataset import (
     23     BertTokenClassificationDataset,

~/opt/anaconda3/lib/python3.9/site-packages/nemo/collections/nlp/data/question_answering_squad/qa_dataset.py in <module>
     26 
     27 from nemo.collections.common.parts.utils import _compute_softmax
---> 28 from nemo.collections.nlp.data.question_answering_squad.qa_squad_processing import (
     29     SquadProcessor,
     30     apply_no_ans_threshold,

~/opt/anaconda3/lib/python3.9/site-packages/nemo/collections/nlp/data/question_answering_squad/qa_squad_processing.py in <module>
     20 
     21 from tqdm import tqdm
---> 22 from transformers.tokenization_bert import BasicTokenizer
     23 
     24 from nemo.collections.nlp.data.data_utils import DataProcessor, is_whitespace, normalize_answer

ModuleNotFoundError: No module named 'transformers.tokenization_bert'
```

The same error was faced by #1566

The suggested fix was to uninstall the latest transformer and revert to 3.5
```
!pip uninstall transformers
!pip install transformers==3.5
```

However, i met this issue when installing transformer 3.5
```
Collecting sentencepiece==0.1.91
  Using cached sentencepiece-0.1.91.tar.gz (500 kB)
  Preparing metadata (setup.py) ... error
  error: subprocess-exited-with-error
  
  × python setup.py egg_info did not run successfully.
  │ exit code: 1
  ╰─> [5 lines of output]
      Package sentencepiece was not found in the pkg-config search path.
      Perhaps you should add the directory containing `sentencepiece.pc'
      to the PKG_CONFIG_PATH environment variable
      No package 'sentencepiece' found
      Failed to find sentencepiece pkgconfig
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: metadata-generation-failed

× Encountered error while generating package metadata.
╰─> See above for output.
```

How do i proceed with the above, or is there another fix where i do not have to revert to transformer 3.5?

Thank you!
