#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::net::Ipv4Addr;
fn main() {
    assert_eq!(Ipv4Addr::new(127, 0, 0, 1).is_loopback(), true);
    assert_eq!(Ipv4Addr::new(45, 22, 13, 197).is_loopback(), false);
}