Your problem can be simplified :
class A: pop = 11 def __del__(self): print A.pop
if __name__ == '__main__': objA = A()
I got the same error message, and I don't know why ? it looks like the class variable can't be accessed from __del__?
It's interesting to note that self.pop instead of A.pop works as expected. But I don't know why A.pop doesn't. -- http://mail.python.org/mailman/listinfo/python-list
