The referenced filename should be `ispklTutorialPart3.pkl`, not `pklTutorial.pkl`.
Also, changes dates from 2023 to 2024
Co-authored-by: grant-abbott <gaabbott@apple.com>
Currently, typed objects are only briefly mentioned in the sentence
stating that (typed) objects cannot be amended with new properties, only
existing ones. This is unnecessarily confusing since all examples up
until that point have been concerned with dynamic objects. Since the
tutorial goes on to amend a dynamic object with a new property in the
next section, a reader who isn't yet aware there are two types of
objects might be confused by what seems to be a contradiction.
Running through the tutorial, the amending was stated in the tutorial text but not visible in the tutorial output since `parrot.pkl` was replacing all the members of `pigeon.pkl`.
