> The list constructor does not overallocate the internal item buffer if the input iterable has a known length (the input implements __len__). This makes the cr

> The list constructor does not overallocate the internal item buffer if the input iterable has a known length (the input implements __len__). This makes the created list 12% smaller on average. (Contributed by Raymond Hettinger and Pablo Galindo in bpo-33234.) Wow. I believe it's a stated goal of CPython to prefer simple maintainable code over maximum performance. But relatively low-hanging fruit like this makes me wonder how much overall CPython perf could be improved by specialising for a few more of these.