Simple slicing question

[Nikhil R. Deshpande]

Python 2.2 (#28, Dec 21 2001, 12:21:22) [MSC 32 bit (Intel)] on win32
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>>> a = [1, 2, 3]
>>> a[100:200]
[]

Why doesn't a[100:200] result in an IndexError?

Thanks,
 Nikhil