Doc nit.
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index 3c9f334..2736263 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -96,7 +96,7 @@
             total = next(it)
             yield total
             for element in it:
-                total += element
+                total = total + element
                 yield total
 
     .. versionadded:: 3.2