#![allow(dead_code, deprecated, unused_variables, unused_mut)]
use std::cell::OnceCell;
fn main() {
    let cell = OnceCell::new();
    assert!(cell.get().is_none());
    assert_eq!(cell.set(92), Ok(()));
    assert_eq!(cell.set(62), Err(62));
    assert!(cell.get().is_some());
}