Update app.py

app.py

@@ -8,6 +8,7 @@ from langchain.text_splitter import RecursiveCharacterTextSplitter
 from langgraph.graph import END, StateGraph
 from typing_extensions import TypedDict, Annotated
 from typing import Sequence, Dict, List, Optional, Any
+from langgraph.graph.message import add_messages
 import chromadb
 import os
 import streamlit as st