Update back.py

back.py

@@ -4,7 +4,7 @@ from typing import List, Dict, Any, Optional, Union
 from dataclasses import dataclass
 import torch
 from sentence_transformers import SentenceTransformer
-from langchain.vectorstores import FAISS
+from langchain_community.vectorstores import FAISS
 from langchain_core.embeddings import Embeddings
 import google.generativeai as genai
 from datetime import datetime