Give python ability to call function that takes reference

[w14]

I have a function that takes a reference and other arguments, I would like to be able to call it from python.

fn f(t: &T, a: usize) -> PyResult<...> {
    ...
}

fn main() {
    let x: &T = T::new();
    ... call python and pass "x" and "f", while allowing python to call "f(x, n)" ...
}

How do you do this?