A few years ago, I worked on a (company-strategic) experimental project that used Python. Apparently, it only worked on some specific versions of Python, due to

A few years ago, I worked on a (company-strategic) experimental project that used Python. Apparently, it only worked on some specific versions of Python, due to changes in the internal order of sets, a fact that was of course not documented or checked in the tool. Not the reason for which the project failed, but the weeks lost trying to replicate results between teams certainly didn't help. Python is very readable, but I agree that the stdlib is anything but simple.