Bizarre error from help()

[Roy Smith]

Can anybody explain this bizarre behavior:

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Roy-Smiths-Computer:play$ py
Python 2.3.4 (#3, Jun 29 2004, 21:48:03)
[GCC 3.3 20030304 (Apple Computer, Inc. build 1495)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

help (isinstance) foos bars bazes
Foo
Traceback (most recent call last):
File "<stdin>", line 1, in ?
File "/usr/local/lib/python2.3/site.py", line 307, in __call__
import pydoc
File "/usr/local/lib/python2.3/pydoc.py", line 49, in ?
from string import expandtabs, find, join, lower, split, strip, rfind,
rstrip
ImportError: cannot import name expandtabs

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