diff --git a/Lib/configparser.py b/Lib/configparser.py
index 924cc56a3f150d..b075304ed631d8 100644
--- a/Lib/configparser.py
+++ b/Lib/configparser.py
@@ -129,7 +129,7 @@
     remove_option(section, option)
         Remove the given option from the given section.
 
-    set(section, option, value)
+    set(section, option, value=None)
         Set the given option.
 
     write(fp, space_around_delimiters=True)