I realize it does become an instance variable as soon as it is assigned a value, hence I was perplexed as to why it did not have the intended effect. Thanks for pointing out that the name is mangled. That clarifies it! I forgot about name mangling (although I did realize attrs starting with '_' are intended to be implementation detail private).
In any case, I do not replicate the logic of allContentReceived () anymore. Instead, I just call the base class method in my derived class.
I had to have a derived class because the following line throws an exception: req = self.requests[-1] because of my special handing of the request connection (the req is gone by the time allContentReceived() gets called). What is my special handling? I tie up the request using producer/consumer to some other resource before the entire content is received.
So for now I am fine with: DerivedClass::allContentReceived(self): try: http.HTTPChannel.allContentReceived(self) except Exception, e: pass
Speaking of derived classes, ... I will pose a related question on a new thread ...