Update app.py

app.py

@@ -8,6 +8,10 @@ import re
 from huggingface_hub import hf_hub_download
 from huggingface_hub import HfApi, login
 from datetime import datetime
+from langchain_openai import ChatOpenAI
+from langchain.chains import create_retrieval_chain
+from langchain.chains.combine_documents import create_stuff_documents_chain
+from langchain_core.prompts import ChatPromptTemplate
 
 from manabUtils import retrieve_chunks