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: lib.rs
    path of file: ./repos/chrono/src
    
    the code of the file until where you have to start completion: //! # Chrono: Date and Time for Rust
//!

//! Chrono aims to provide all functionality needed to do correct operations on dates and times in the
//! [proleptic Gregorian calendar](https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar):
//!
//! * The [`DateTime`](https://docs.rs/chrono/latest/chrono/struct.DateTime.html) type is timezone-aware
//!   by default, with separate timezone-naive types
    
//! # fn test() {
//! let dt = Utc.with_ymd_and_hms(2014, 11, 28, 12, 0, 9).unwrap();
//! assert_eq!(dt.format("%Y-%m-%d %H:%M:%S").to_string(), "2014-11-28 12:00:09");
//! assert_eq!(dt.format("%a %b %e %T %Y").to_string(), "Fri Nov 28 12:00:09 2014");
//! assert_eq!(
//!     dt.format_localized("%A %e %B %Y, %T", Locale::fr_BE).to_string(),
//!     "vendredi 28 novembre 2014, 12:00:09"
//! );
//!
//! assert_eq!(dt.format("%a %b %e %T %Y").to_string(), dt.format("%c").to_string());
//! assert_eq!(dt.to_string(), "2014-11-28 12:00:09 UTC");
//! assert_eq!(dt.to_rfc2822(), "Fri, 28 Nov 2014 12:00:09 +0000");
//! assert_eq!(dt.to_rfc3339(), "2014-11-28T12:00:09+00:00");
//! assert_eq!(format!("{:?}", dt), "2014-11-28T12:00:09Z");
//!
//! // Note that milli/nanoseconds are only printed if they are non-zero
//! let dt_nano = NaiveDate::from_ymd_opt(2014, 11, 28)
//!     .unwrap()
//!     .and_hms_nano_opt(12, 0, 9, 1)
//!     .unwrap()
//!     .and_local_timezone(Utc)
//!     .unwrap();
//! assert_eq!(format!("{:?}", dt_nano), "2014-11-28T12:00:09.000000001Z");
//! # }