Issues: Adding a FAISS or Elastic Search index to a Dataset
@lhoestq  I tried installing transformer from the master branch. Python imports for DPR again didnt' work.  Anyways, Looking forward to trying it in the next release of nlp 
It seems the DPRContextEncoder, DPRContextEncoderTokenizer cited[ in this documentation](https://huggingface.co/nlp/faiss_and_ea.html) is not implemented ? It didnot work with the standard nlp installation . Also, I couldn't find or use it with the latest nlp install from github in Colab.  Is  there any dependency on the latest PyArrow 1.0.0 ? Is it yet to be made generally available ?
Issues: Adding a FAISS or Elastic Search index to a Dataset 
 It seems the DPRContextEncoder, DPRContextEncoderTokenizer cited[ in this documentation](https://huggingface.co/nlp/faiss_and_ea.html) is not implemented ? It didnot work with the standard nlp installation . Also, I couldn't find or use it with the latest nlp install from github in Colab.  Is  there any dependency on the latest PyArrow 1.0.0 ? Is it yet to be made generally available ? 
 @lhoestq  I tried installing transformer from the master branch. Python imports for DPR again didnt' work.  Anyways, Looking forward to trying it in the next release of nlp 