public Laptop(string model, double price, string manufacturer = null, string cpu = null, string ram = null, string gpu = null, string hdd = null, Battery battery = null, string screen = null)
{
this.Model = model;
this.Price = price;
this.Manufacturer = manufacturer;
this.CPU = cpu;
this.RAM = ram;
this.GPU = gpu;
this.HDD = hdd;
this.Battery = battery;
this.Screen = screen;
}