[Zope] UnpickleableError with objects derived from Sync.Synchronized

[Chris McDonough]

This signifies that your instance has a reference to another object that 
cannot be pickled.  For a list of items that are pickleable (and 
therefore storable in the ZODB), see the Python documentation.

Alexei Ustyuzhaninov wrote:
> Hi!
> 
> I have objects in my product which shouldn't be accessed simultaneously 
> by different threads. So I mixed their class in the Sync.Synchronized 
> class as recommended in 
> http://www.zope.org/Documentation/How-To/ThreadSafety. But now I can't 
> even create the objects because of UnpickleableError:
> 
> Traceback (innermost last):
>   File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 223, in 
> publish_module
>   File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 187, in publish
>   File /usr/lib/zope/lib/python/Zope/__init__.py, line 226, in 
> zpublisher_exception_hook
>   File /usr/lib/zope/lib/python/ZPublisher/Publish.py, line 175, in publish
>   File /usr/lib/zope/lib/python/Zope/__init__.py, line 240, in commit
>   File /usr/lib/zope/lib/python/ZODB/Transaction.py, line 302, in commit
>   File /usr/lib/zope/lib/python/ZODB/Connection.py, line 418, in commit
>     (Info: (('Products.Tap3Editor.tap3editor', 'tap3editor'), 
> '\x00\x00\x00\x00\x00\x00j\x08', ''))
> UnpickleableError: (see above)
> 
> I use zope 2.4.2 for linux from debian binary distribution.
> 
> So could someone explain what's the problem here?
>