the list [<__main__.Number instance at 0x8114bb4>, <__main__.Number instance at 0x81044e4>, <__main__.String instance at 0x8146b14>, <__main__.Tuple instance at 0x81470d4>, <__main__.String instance at 0x810e86c>] traversing the list NUM(10) NUM(999) STRING(hello) TUPLE(3,4) STRING(End) instantiating Object Traceback (most recent call last): File "polymorph.py", line 47, in ? o=Object() File "polymorph.py", line 3, in __init__ raise Exception, "attempting to instantiate ABSTRACT base class" Exception: attempting to instantiate ABSTRACT base class