static GSM()
 {
     Iphone4s = new GSM("Iphone 4s",
                        "Apple",
                        new Battery("2550mAh", "Samsung", BatteryCellType.LiIon),
                        new Display("Xreality", "Sony", 4.3f, 16e6f));
 }
        public void SwichBattery(GSM mobile2)
        {
            var mobile1Bat = this.TakeOutBattery();
            var mobile2Bat = mobile2.TakeOutBattery();

            this.Battery    = mobile2Bat;
            mobile2.Battery = mobile1Bat;
        }