Update app.py

app.py

@@ -1,7 +1,8 @@
 from llama_cpp import Llama
 import streamlit as st
 from langchain.llms.base import LLM
-from llama_index import LangchainEmbedding, ServiceContext, PromptHelper
+from llama_index.embeddings import LangchainEmbedding
+from llama_index import PromptHelper
 from typing import Optional, List, Mapping, Any
 from langchain.embeddings.huggingface import HuggingFaceEmbeddings
 import pandas as pd