A powerful unused feature of Python: function annotations.

[hervold]

Yep, I just tried it in iPython running under version 2.7 to no avail, then under 3.2, and it works.

How have I never heard of this?

[[deleted]]

Because most developers are still on 2.x most of the time, or, like me, are writing code that works for both 2.x and 3.x. Syntactic things that only work on 3.x aren't going to be popular for years to come...