vincenzo@earth:~$ python
Python 2.5.1 (r251:54863, Oct  5 2007, 13:36:32) 
[GCC 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> a = [1, 2, 3]
>>> a.index(2)
1
>>> class test:
...     def __init__(self, a):
...             self.a = a
... 
>>> list = [test('hello'), test('world')]
>>> print list  
[<__main__.test instance at 0xb7d8ed4c>, <__main__.test instance at 0xb7d8eccc>]
>>> list.index(test('hello'))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: list.index(x): x not in list
>>>