Fail to parse standard cron

[JosiahParry]

The following standard cron schedule fails to parse:

fn main() {
    let res = "0 0 * * 0".parse::<CronExpr>();
    let description = res.unwrap().describe(English::default()).to_string();
    println!("{description}");
}
// thread 'main' panicked at src/main.rs:9:27:
// called `Result::unwrap()` on an `Err` value: CronParseError(())

it should read something like "At midnight every sunday". However "0 0 * * 1" results in the correct value even though the 1 represents monday.