The doc for pprint.PrettyPrinter at https://docs.python.org/3/library/pprint.html says:

    If sort_dicts is true (the default), dictionaries will be formatted with their keys sorted, otherwise they will display in insertion order

I believe the insertion order is not even known by normal dicts (only by OrderedDict), so I think the last phrase must be wrong. If it's somehow correct, it deserves explaining....