public abstract void Remove(Senior senior);
public abstract void Add(Senior senior);
public override void Remove(Senior senior) { Console.WriteLine("Student is the junior most.. Nothing to remove"); }
public override void Add(Senior senior) { Console.WriteLine("Student is the junior most so cannot add more"); }
public override void Remove(Senior senior) { _seniors.Remove(senior); }
public override void Add(Senior senior) { _seniors.Add(senior); }