[davvid]

While I mostly wrote `mutuple` for fun, it's also a proof of concept for solving a tricky pickling problem in the jsonpickle[1] library: restoring object graphs that contain tuples with back-references to the same tuple.

I'm pretty sure there are better ways of handling this edge case, but, hey, it works and was a pretty fun experiment.

[1] https://github.com/jsonpickle/jsonpickle/pull/491