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: ema.rs
    path of file: ./repos/ta-rs/examples
    
    the code of the file until where you have to start completion: use ta::indicators::ExponentialMovingAverage as Ema;
use ta::DataItem;
use ta::Next;

fn main() {
    let mut ema = Ema::new(9).unwrap();
    let mut reader = csv::Reader::from_path("./examples/data/AMZN.csv").unwrap();

    for record in reader.deserialize() {
  
    
fn main() {
    let mut ema = Ema::new(9).unwrap();
    let mut reader = csv::Reader::from_path("./examples/data/AMZN.csv").unwrap();

    for record in reader.deserialize() {
        let (date, open, high, low, close, volume): (String, f64, f64, f64, f64, f64) =
            record.unwrap();
        let dt = DataItem::builder()
            .open(open)
            .high(high)
            .low(low)
            .close(close)
            .volume(volume)
            .build()
            .unwrap();
        let ema_val = ema.next(&dt);
        println!("{}: {} = {:2.2}", date, ema, ema_val);
    }
}