The usual (and some new modules).

Lib/dos-8x3/test_opc.py

@@ -28,6 +28,9 @@ print '2.2 raise class exceptions'
 class AClass: pass
 class BClass(AClass): pass
 class CClass: pass
+class DClass(AClass):
+    def __init__(self, ignore):
+	pass
 
 try: raise AClass()
 except: pass
@@ -46,18 +49,22 @@ a = AClass()
 b = BClass()
 
 try: raise AClass, b
-except BClass, v: raise TestFailed
-except AClass, v:
+except BClass, v:
 	if v != b: raise TestFailed
-
+else: raise TestFailed
 
 try: raise b
 except AClass, v:
 	if v != b: raise TestFailed
 
+# not enough arguments
 try:  raise BClass, a
 except TypeError: pass
 
+try:  raise DClass, a
+except DClass, v:
+    if not isinstance(v, DClass):
+	raise TestFailed
 
 print '2.3 comparing function objects'