Forms (and models) in Django are one such thing. When you define fields on a form at the class level, Django maintains a global counter so the fields can retain their order with respect to each other.

Now, with ordered dictionaries, that order is maintained for free.

Kwarg order in functions is also maintained as far as I know.

One thing I do frequently is create an ordered dict where the keys are either regex patterns or lambda functions that return true or false; and the values are some sort of label (let’s say some sort of document type). Then I’ll create a function that will take that ordered dict plus some data, and return the first label that the data conforms to (e.g. regex pattern matches some text input)

This is a handy way of making classification rules for a many stepped process, where certain rules have priority over others. The alternative would be a lengthy set of ifs and elifs which is both ugly and not fun to edit on the fly.