This is Python 2.4.4 on Debian Etch.

Look at the following interpreter session:

    Python 2.4.4c0 (#2, Jun 14 2006, 22:35:41)
    [GCC 4.1.2 20060613 (prerelease) (Debian 4.1.1-4)]
        on linux2
    Type "help", "copyright", "credits" or "license"
for more information.
    >>> import shelve
    >>> import anydbm
    >>> try:
    ...     shelve.open('nonexistent', 'r')
    ... except anydbm.error:
    ...     print 'caught it'
    ... 
    caught it
    Exception exceptions.AttributeError:
"DbfilenameShelf instance has no
    attribute 'writeback'" in  ignored
    >>> anydbm.error
    (<class anydbm.error at 0xb7f48bfc>,
     <class bsddb._db.DBError at 0xb7f5623c>,
     <class gdbm.error at 0xb7f48cbc>,
     <class dbm.error at 0xb7f5b38c>,
     <class exceptions.IOError at 0xb7f774ac>)
    >>>

Shelf.__del__() calls Shelf.close() calls Shelf.sync()
which
references self.writeback even though that attribute
doesn't exist.
It also references self.dict which also doesn't exist.