fn backup_id_valid(backup_id: &str) -> bool {
    backup_id.len() == 64
        && backup_id
            .chars()
            .all(|c| c.is_ascii_hexdigit() && (c.is_digit(10) || c.is_lowercase()))
}
/// Return whether this backup id is valid.
///
/// A backup id must be a 64 character lowercase hex string.
Return whether this backup id is valid.
A backup id must be a 64 character lowercase hex string.
Return whether this backup id is valid . A backup id must be a 64 character lowercase hex string .
fn backup_id_valid(backup_id: &str) -> bool {
    backup_id.len() == 64
        && backup_id
            .chars()
            .all(|c| c.is_ascii_hexdigit() && (c.is_digit(10) || c.is_lowercase()))
}
fn backup_id_valid ( backup_id : & str ) -> bool { backup_id . len ( ) == 64 && backup_id . chars ( ) . all ( | c | c . is_ascii_hexdigit ( ) && ( c . is_digit ( 10 ) || c . is_lowercase ( ) ) ) }
Return whether this backup id is valid.
Return whether this backup id is valid .
backup_id
&str
backup_id
&str