Lots of small changes, including this interesting one[1]. Why anyone was monkeypatching `len()` with a version wrapped in a `lru_cache` is beyond me!<p>Another good one is this[2], which improves the speed of creating dictionary literals with constant keys by 30% (i.e {'a': 1, 'b': 2}.<p>The full changelog is here: <a href="https://docs.python.org/3.6/whatsnew/changelog.html" rel="nofollow">https://docs.python.org/3.6/whatsnew/changelog.html</a><p>1. <a href="https://bugs.python.org/issue28991" rel="nofollow">https://bugs.python.org/issue28991</a><p>2. <a href="https://bugs.python.org/issue28731" rel="nofollow">https://bugs.python.org/issue28731</a>