handle_expt_event was removed in the test classes because it is no 
longer being used by any of the tests.  None of them send OOB data (also 
known as priority data), so handle_expt_event should never be called.  
When I have a chance to compare your patch to mine (Monday, likely), 
I'll comment then.

In terms of "handle_expt_event should handle the low level expt event 
called from select", what you don't seem understand is that and "expt 
event" is not an exception event, it's a "we got OOB data" event, and 
with the patches, it is called at *exactly* the time it should be: when 
there is OOB data.  It used to be mistakenly called in the select loop 
whenever any sort of non-normal condition happened on the socket, which 
was a serious design flaw, and lead to significant misunderstanding 
about the purpose of the method.

With the _exception() call as-is, it now behaves like the 
asyncore.poll2() function, which is the right thing.