diff --git a/IPython/core/history.py b/IPython/core/history.py
index 4ffdd54..2967003 100644
--- a/IPython/core/history.py
+++ b/IPython/core/history.py
@@ -22,7 +22,6 @@ import sqlite3
 import threading
 
 from collections import defaultdict
-from contextlib import nested
 
 # Our own packages
 from IPython.config.configurable import Configurable