Update app.py

app.py

@@ -1,4 +1,3 @@
-from langchain.document_transformers import LongContextReorder
 from langchain_core.runnables import RunnableLambda
 from langchain_core.runnables.passthrough import RunnableAssign
 from langchain_nvidia_ai_endpoints import ChatNVIDIA, NVIDIAEmbeddings
@@ -17,7 +16,9 @@ from langchain_nvidia_ai_endpoints import ChatNVIDIA, NVIDIAEmbeddings
 
 from langchain_community.vectorstores import FAISS
 from langchain.text_splitter import RecursiveCharacterTextSplitter
-from langchain.document_loaders import ArxivLoader
+from langchain_community.document_loaders import ArxivLoader
+from langchain_community.document_transformers import LongContextReorder
+
 
 import os