public void Notify(IObservable sender, WeatherInfo info)
 {
     foreach (var item in observers)
     {
         item.Update(this, info);
     }
 }
 public void Update(IObservable sender, WeatherInfo info)
     => Console.WriteLine("Statistic");
 public void Update(IObservable sender, WeatherInfo info)
 => Console.WriteLine("ForeCast");
 public void Update(IObservable sender, WeatherInfo info) => Console.WriteLine("CurrentConditions");
 public WeatherData()
 {
     observers   = new List <IObserver>();
     WeatherInfo = new WeatherInfo();
 }