#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::iter;
fn main() {
    let mut fours = iter::repeat(4);
    assert_eq!(Some(4), fours.next());
    assert_eq!(Some(4), fours.next());
    assert_eq!(Some(4), fours.next());
    assert_eq!(Some(4), fours.next());
    assert_eq!(Some(4), fours.next());
    assert_eq!(Some(4), fours.next());
}