Update app.py

app.py

@@ -17,6 +17,7 @@ from langchain.retrievers import EnsembleRetriever
 from langchain_community.vectorstores import FAISS
 from langchain_groq import ChatGroq
 from pinecone import Pinecone, ServerlessSpec
+from pinecone_text.sparse import BM25Encoder
 from langchain import hub
 import pickle
 import os