diff --git a/src/calibre/utils/ipython.py b/src/calibre/utils/ipython.py
index 080b43b591..d31d6e0dfd 100644
--- a/src/calibre/utils/ipython.py
+++ b/src/calibre/utils/ipython.py
@@ -168,7 +168,8 @@ def ipython(user_ns=None):
     if not user_ns:
         user_ns = defns
     else:
-        user_ns = defns.update(user_ns)
+        defns.update(user_ns)
+        user_ns = defns
 
     c = Config()
     c.InteractiveShellApp.exec_lines = [