I can see that there are ways that I can change my tests.  I see that there are third-party libraries that can help me with this.

But changing the behavior of the standard library, without a way to retain the old behavior, and asking people to adapt by changing their test suites, seems a bit cavalier.

Why not add an option to keep the sorting that the standard library has always had?  I'll even be OK with changing the default behavior to unsorted, just give me a way to explicitly keep the behavior its always had in the past.

The discussion so far has 1) hypothesized that test suites would be broken, and 2) claimed that no one needs the output in sorted order.  I can tell you that my test suite is broken, and that removing the sorted order is what broke it.

The json module has the option to sort keys.  toprettyxml already has options well outside the needs of XML semantics (indent and newl).

Let's honor Python's tradition of standard library stability, and give me a way to keep the behavior I used to have.