Did I make a mistake by thinking that the Polars Python port has more features than the one in Rust?

Just started learning about Polars, I hope I am wrong, but it seems like many features are missing in Rust while available in Python, even through Polars is written in Rust. Just pick some of them:

1. selectors,
   I don't know what it is exactly, but when I read through the user guide, it is said that this is not available in Rust
2. Some handy functions, like describe or approx_n_unique are also missing.