I know it's a bit of trope to say this on HN... but why not Lisp?

If I make the assumption that future ML code will be written by ML algorithms (or at least 'transpiled' from natural language), and Lisp S-Expressions are basically the AST, it would make sense that it would be the most natural language for a machine to write in. As a side benefit, it's already the standard to have a very feature complete REPL, so as a replacement for Python it seems it would fit well