Update app.py

app.py

@@ -1,9 +1,9 @@
 from transformers import GPT2LMHeadModel, GPT2Tokenizer
-from langchain import PromptTemplate
+from langchain_core.prompts import PromptTemplate
 from langchain_huggingface import HuggingFaceEmbeddings
 from langchain_community.vectorstores import FAISS
 from langchain.chains import RetrievalQA
-from langchain_core import RunnableSequence
+from langchain.chains.sequential import SequentialChain
 import gradio as gr
 
 DB_FAISS_PATH = "vectorstores/db_faiss"