I fixed this as discussed, but:
- I didn't use `last()` because it's only available for `DatetimeIndex`
- I didn't use `.iloc[-1]` because there are a lot of stern warnings in the docs do don't use it and I don't want to confuse less technically aligned user by now using it in an "official" sample
- I did use `.iat[-1]` because it's supposed to be fasted by working on the Series of the requested column directly