diff --git a/langchain/docstore/base.py b/langchain/docstore/base.py
index 35f75f5c489..915707926f6 100644
--- a/langchain/docstore/base.py
+++ b/langchain/docstore/base.py
@@ -8,12 +8,13 @@ from pathlib import Path
 from typing import (
     Dict,
     Generic,
+    Iterable,
     Iterator,
     List,
     Optional,
     Sequence,
     TypeVar,
-    Union, Iterable,
+    Union,
 )
 
 from langchain.docstore.document import Document