Rust python module with pyo3

py_math.rs

use pyo3::{
    prelude::pyfunction, prelude::pymodule, types::PyModule, wrap_pyfunction, PyResult, Python,
};

#[pyfunction]
fn sum_numbers(a: usize, b: usize) -> PyResult<usize> {
    Ok(a + b)
}

#[pymodule]
fn py_math(_py: Python, m: &PyModule) -> PyResult<()> {
    m.add_function(wrap_pyfunction!(sum_numbers, m)?)?;
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_sum_numbers() {
        assert_eq!(5, sum_numbers(2, 3).expect("cant sum"));
    }
}