I guess it is hard to see what the code is doing without a complete example.
The StopIteration is actually raised by task.next(), at which point task is removed from the list of generators (self.pool). So the StopIteration can be raised at any time. The specific optimisation I am after, which will clean up the code a lot, is a way to auto-magically create self_attribute local variables from self.attribute instance variables. Sw. -- http://mail.python.org/mailman/listinfo/python-list
