code: def __init__(self, retrievers):
      self.retriever_pool = {}
      for retriever in retrievers["options"]:
          if retriever["value"] in self.retriever_pool:
              raise ValueError(
                  "Duplicate retriever value : {} ".format(
                      retriever["value"]
                  )
              )
  
          if retriever["type"] == "elasticsearch":
              self.retriever_pool[
                  retriever["value"]
              ] = ElasticSearchRetriever(**retriever["connection"])
          if retriever["type"] == "solr":
              logger.info("We do not yet support Solr retrievers")
      self.selected_retriever = retrievers["selected"]
  
imports: from neuralqa.retriever import ElasticSearchRetriever
  import logging
label_desc: Use image node_id 1 to create a new RetrieverPool object  with example: obj = RetrieverPool(retrievers)