public static void RemoveElevator(Elevator elevator)
{
if (elevators.TryRemove(elevator.GetHashCode(), out elevator))
{
Console.WriteLine("-" + elevator + " is OUT OFF Service.");
}
}
public static void AddElevator(Elevator elevator)
{
if (elevators.TryAdd(elevator.GetHashCode(), elevator))
{
Console.WriteLine("+" + elevator + " is IN Service.");
}
}