Get file extension Rust

fileextension.rs

use std::path::Path;
use std::ffi::OsStr;

fn main() {
fn get_extension_from_filename(filename: &str) -> Option<&str> {    
Path::new(filename)        
.extension()        
.and_then(OsStr::to_str)}

assert_eq!(get_extension_from_filename("abc.gz"), Some("gz"));
println!("{:?}",get_extension_from_filename("abc.gz"));

}