Update app.py

app.py

@@ -11,7 +11,7 @@ from langchain_text_splitters import RecursiveCharacterTextSplitter
 from langchain_pinecone import PineconeVectorStore
 from langchain_groq import ChatGroq
 from langchain_classic.chains import create_retrieval_chain
-from langchain.chains.combine_documents import create_stuff_documents_chain
+from langchain_classic.chains.combine_documents import create_stuff_documents_chain
 from langchain_core.prompts import ChatPromptTemplate
 from langchain_core.embeddings import Embeddings