Use preferred form of raising exceptions.
diff --git a/Doc/tutorial/controlflow.rst b/Doc/tutorial/controlflow.rst
index 95a6ea4..cc1d334 100644
--- a/Doc/tutorial/controlflow.rst
+++ b/Doc/tutorial/controlflow.rst
@@ -315,7 +315,7 @@
            if ok in ('y', 'ye', 'yes'): return True
            if ok in ('n', 'no', 'nop', 'nope'): return False
            retries = retries - 1
-           if retries < 0: raise IOError, 'refusenik user'
+           if retries < 0: raise IOError('refusenik user')
            print complaint
 
 This function can be called either like this: ``ask_ok('Do you really want to