$ python iterator_test.py 463 926 1389 1852 Let’s take a look at what’s going on. We made our own class and defined a __next__ method, which returns a new iteration every time it’s called.

On this benchmark, Python 3.5.2 cranked out 34.3 nanoseconds per iteration. Python 3.6 beta 1 brought that number down to 29.8.