[tagyro]

yes, they were (theoretically) a python developer, should have mentioned this was an ML role (your guess is right, slice just before the last char)

Just to be clear: the main problem is not that they did not know what `:-1` was - there are many weird syntax additions with every version - understandable.

IMHO the problem is that there's usually a single interviewer that decides go/no go.

We all have biases, so leaving such an important decision (like hiring an EM) to one person is, (again IMHO) ...stupid .