> I met someone who was specifically using `dict()` instead of `{}` because, he told me, the CPython parser was much slower on the later than on the former and that it was noticeable on larger code base.

I've been told by code reviewers to use micro-optimisations like this before.

My default reply is "I think this way is faster, since the shorter code results in fewer cache misses. I'd be happy to change it if you show me some benchmarks."

Of course, the cache may or may not affect anything; the point is to burst their philosophical bubble with an example of why measurements are needed.

There's also the good old fashioned "If we cared that much about performance, we wouldn't be using the branching logic of a templating system in an interpreted language."