Forgot to explain the effect of the new opcode.
Sigh -- we really should have one place for all opcode metadata.
diff --git a/Lib/compiler/pyassem.py b/Lib/compiler/pyassem.py
index 7b6cee6..22a19c7 100644
--- a/Lib/compiler/pyassem.py
+++ b/Lib/compiler/pyassem.py
@@ -778,6 +778,7 @@
         'SETUP_EXCEPT': 3,
         'SETUP_FINALLY': 3,
         'FOR_ITER': 1,
+        'WITH_CLEANUP': 3,
         }
     # use pattern match
     patterns = [