This language offers contracts, and built-in unit tests - both of which could probably be done in python (contracts could be done as decorators, I would think),

This language offers contracts, and built-in unit tests - both of which could probably be done in python (contracts could be done as decorators, I would think), but are far from being built-in to the language. Eiffel is the only language I've heard of that uses contracts (I'm sure there's more though). They seem like they could make some aspects of OOP in a dynamically-typed language much easier. Maybe I'm reading you wrong, but it sounds like you think this is a set of changes to python. It's not, it's a different language with some syntax inspired by python. Either way, I don't think their goal is to overtake python - besides, the language is still really young.