You can also consider that open source version of RustPython existed 6 years ago and probably in all LLMs dataset

This is really what people conflagrate so often with these tasks, it is basically making the model do recall what could also be a "ant_ag_ds_90917_rwpy9_final" git clone

CPython is in the training data, but this was a tree walking interpreter, so it wasn't just regurgitating cpython. I capped it as 1000 lines for the first 20% of the project, it is currently 13.3kloc and 575k in a single file.

Rewrite X in Y is an ideal RL task given you have X as an oracle trivially.