diff --git a/docs/topics/auth/customizing.txt b/docs/topics/auth/customizing.txt
index b85d08ad563..4c54e8b986a 100644
--- a/docs/topics/auth/customizing.txt
+++ b/docs/topics/auth/customizing.txt
@@ -1051,7 +1051,7 @@ code would be required in the app's ``admin.py`` file::
 
         class Meta:
             model = MyUser
-            fields = ['email', 'password', 'date_of_birth', 'is_active', 'is_admin']
+            fields = ('email', 'password', 'date_of_birth', 'is_active', 'is_admin')
 
         def clean_password(self):
             # Regardless of what the user provides, return the initial value.