Update app.py

app.py

@@ -10,6 +10,7 @@ from langchain.embeddings import HuggingFaceEmbeddings
 from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
 from langchain.chains import create_history_aware_retriever, create_retrieval_chain
 from langchain.chains.combine_documents import create_stuff_documents_chain
+from langchain_huggingface import HuggingFaceEndpoint
 
 
 os.getenv('HUGGINGFACEHUB_API_TOKEN')