rest of code after improved code

after_improved_code.rs

 // update cab destination and person_id
    nearest_cab.update_destination(Some(person.location.clone()));
    nearest_cab.update_person_id(ObjectId::parse_str(person_id).ok());
    // update cab by using `assign_person`
    let cab_id = match nearest_cab.id {
        Some(obj_id) => obj_id.to_hex(),
        None => panic!("cannot get the cab id"),
    };
    let update_result = db.assign_person(&cab_id, nearest_cab.clone());
    // return result as person and cab tuple
    match update_result {
        Ok(update) => {
            if update.matched_count == 1 {
                let updated_cab_info = db.get_cab(&cab_id);
                match updated_cab_info {
                    Ok(cab) => Ok(Json((person, cab))),
                    Err(_) => Err(Status::InternalServerError),
                }
            } else {
                Err(Status::NotFound)
            }
        }
        Err(_) => Err(Status::InternalServerError),