Shelve and classes

[Curtis Jensen]

I have several data classes (only contain array data).  I want to use
shelve to save this data to a database.  I tried and this is what I got:

>>> import shelve
>>> d = shelve.open('tmp.db')
>>> d['nodes'] = nodes
Traceback (innermost last):
  File "<stdin>", line 1, in ?
  File "/usr/local/Python/lib/python1.5/shelve.py", line 71, in
__setitem__
    self.dict[key] = f.getvalue()
dbm.error: Cannot add item to database
>>> 

nodes was already declared as an instance of one of my classes.  What am
I doing wrong?  Thanks.

-- 
Curtis Jensen
cjensen at bioeng.ucsd.edu
http://www-bioeng.ucsd.edu/~cjensen/
FAX (425) 740-1451