fn parse_year(year: &[u8]) -> Option<u16> {
    match parse_4_digits(year) {
        Some(year) => Some(year),
        _ => None,
    }
}
/// Parse a 4-digit year
Parse a 4-digit year
Parse a 4 - digit year
fn parse_year(year: &[u8]) -> Option<u16> {
    match parse_4_digits(year) {
        Some(year) => Some(year),
        _ => None,
    }
}
fn parse_year ( year : & [ u8 ] ) -> Option < u16 > { match parse_4_digits ( year ) { Some ( year ) => Some ( year ) , _ => None , } }
Parse a 4-digit year
Parse a 4 - digit year
year
&[u8]