Logged In: YES 
user_id=671362

I've verified that recent Python raises "RuntimeError : 
deque mutated during iteration" against my program.

Thanks Raymond.

Before submitting this, I tested on Cygwin and it looks like 
my Cygwin had a problem with libinstall.
That is why not all the libraries were installed properly in
the process of "make install".

Sorry about that.