time complexity of [::-1] in python code example

Example: find time complexity of python code

It’s not possible for a code calculating time complexity of any given code to exist (of course might be there can exist programs which can deal correctly with very simple cases, although I’m not aware of one but some software validation softwares I guess could quite possibly have such simple - and this likely means very simple indeed - analysers). And by that statement I don’t mean that no one has yet come up with how to write such a code, but that it’s been proven no such code can ever be written. That’s one of the reasons why we spend time proving what a complexity of algorithm is as it’s one of the things which only a human (or AI better than the ones we have now) can hope to achieve. Just think about it, to write such a code you would need to take any code someone wrote and be able to analyse how it will behave on any possible of infinitely many possible inputs, and the analysis of those infinitely many inputs you would’ve need to perform in any reasonable (well, finite, in the first place) time.