Python 3 ...

[lifthrasiir]

http://mail.python.org/pipermail/pypy-dev/2013-May/011394.html

[jumblesale]

The same functionality in Perl: https://www.inkling.com/read/programming-perl-christiansen-4...

It's a fun feature but saying it's the main reason to upgrade to Python 3 is going a bit far. I don't see how it's much different to something like # TODO: implement this method! or raise NotImplementedError if you don't want it to be invoked.

[dalke → jumblesale]

It's sarcasm. You can tell because of the "Even worse" and "</rant>".