1 files changed, 1 insertions, 1 deletions
diff --git a/Lib/UserDict.py b/Lib/UserDict.py
index 87cc6a3..703f118 100644
--- a/Lib/UserDict.py
+++ b/Lib/UserDict.py
@@ -113,7 +113,7 @@ class DictMixin:
     def clear(self):
         for key in self.keys():
             del self[key]
-    def setdefault(self, key, default):
+    def setdefault(self, key, default=None):
         try:
             return self[key]
         except KeyError: