class_docstr: Abstract class for Retrieval Service. 
docstr: Add documents to the Faiss index
  Args:
      docs: List[str], list of documents that is going to be added to the index
      add_eos: bool, whether add the eos in the end
docstr_tok: ["Add","documents","to","the","Faiss","index","Args",":","docs",":","List","[","str","]",",","list","of","documents","that","is","going","to","be","added","to","the","index","add_eos",":","bool",",","whether","add","the","eos","in","the","end"]
code: def add_docs_to_index(self, docs: List[str], add_eos: bool = True):
      """
      Add documents to the Faiss index
      Args:
          docs: List[str], list of documents that is going to be added to the index
          add_eos: bool, whether add the eos in the end
      """
      raise NotImplementedError()
  
imports: import abc
  import logging
  import threading
  from typing import List, Union
  import numpy
  import torch
  from nemo.collections.common.tokenizers.tokenizer_spec import TokenizerSpec
  from nemo.collections.nlp.modules.common.megatron.retrieval_services.util import request_data
label_desc: Use image node_id 2 for calling the RetrievalService obj's underlying member method code with example usage: obj.add_docs_to_index(docs, add_eos) without return types