>>> class A(object):
...     def __getslice__(self, start, stop):
...             print hex(start), hex(stop)
...             return []
...
>>>
>>> a = A()
>>> a[0xbf000000:0xbf0000f0]
0x7fffffff 0x7fffffff
[]
>>> a.__getslice__(0xbf000000,0xbf0000f0)
0xbf000000L 0xbf0000f0L
[]
>>> a[0xbf000000L:0xbf0000f0L]
0x7fffffff 0x7fffffff
[]
>>>