You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: utils.rs
    path of file: ./repos/calamine/src
    
    the code of the file until where you have to start completion: //! Internal module providing handy function

use std::convert::TryInto;

macro_rules! from_err {
    ($from:ty, $to:
    
pub fn push_column(mut col: u32, buf: &mut String) {
    if col < 26 {
        buf.push((b'A' + col as u8) as char);
    } else {
        let mut rev = String::new();
        while col >= 26 {
            let c = col % 26;
            rev.push((b'A' + c as u8) as char);
            col -= c;
            col /= 26;
        }
        buf.extend(rev.chars().rev());
    }
}