Update app.py

Added: from langchain_core.prompts import ChatPromptTemplate

app.py

@@ -9,7 +9,7 @@ from langchain_community.embeddings import HuggingFaceEmbeddings
 # from langchain.chains.combine_documents import create_stuff_documents_chain
 # from langchain.chains import create_retrieval_chain
 # from langchain_core.prompts import ChatPromptTemplate
-
+from langchain_core.prompts import ChatPromptTemplate
 from langchain_classic.chains.combine_documents import create_stuff_documents_chain
 from langchain_classic.chains import create_retrieval_chain
 from langchain_classic.chains import RetrievalQA