diff --git a/Lib/_threading_local.py b/Lib/_threading_local.py
index b006d76c4e23df..3cb55dc507d383 100644
--- a/Lib/_threading_local.py
+++ b/Lib/_threading_local.py
@@ -108,7 +108,7 @@
 local. They are shared across threads:
 
   >>> class MyLocal(local):
-  ...     __slots__ = 'number'
+  ...     __slots__ = ['number']
 
   >>> mydata = MyLocal()
   >>> mydata.number = 42