public LifeLongLicense(string movie, DateTime purchaseTime, Discount discount) : base(movie, purchaseTime, discount) { }
public TwoDaysLicense(string movie, DateTime purchaseTime, Discount discount) : base(movie, purchaseTime, discount) { }
public MovieLicense(string movie, DateTime purchaseTime, Discount discount) { this.Movie = movie; this.PurchaseTime = purchaseTime; this.discount = discount; }