update the tutorial to use str.format
diff --git a/Doc/tutorial/controlflow.rst b/Doc/tutorial/controlflow.rst
index 4b4c819..9b68e57 100644
--- a/Doc/tutorial/controlflow.rst
+++ b/Doc/tutorial/controlflow.rst
@@ -445,8 +445,8 @@
 up in a tuple.  Before the variable number of arguments, zero or more normal
 arguments may occur. ::
 
-   def fprintf(file, format, *args):
-       file.write(format % args)
+   def fprintf(file, template, *args):
+       file.write(template.format(args))
 
 
 .. _tut-unpacking-arguments: