python 2.1b shelve module is broken, on Redhat Linux
6.2:

% python
Python 2.1b1 (#1, Mar 19 2001, 15:18:14)
[GCC 2.95.2 19991024 (release)] on linux2
Type "copyright", "credits" or "license" for more
information.
>>> import shelve
>>> f = shelve.open('testshelve')
>>> f.keys()
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/local/cdat/alpha/lib/python2.1/shelve.py",
line 56, in keys
    return self.dict.keys()
MemoryError