public static void main(String [ ] args){
    WeatherStation weatherStation = new WeatherStation (33);
    WeatherCustomer1 wc1 = new WeatherCustomer1 ();
    WeatherCustomer2 wc2 = new WeatherCustomer2 ();
    weatherStation.addObserver(wc1);
    weatherStation.addObserver(wc2);
    weatherStation.setTemperature (34);
    weatherStation.removeObserver(wc1);
    weatherStation.setTemperature (35);
    }