//•	void Open(int id, string type, int length, string route, int prizePool)
    public void Open(int id, string type, int length, string route, int prizePool)
    {
        //open {id} {type} {length} {route} {prizePool}
        //OPENS a race of the given type, with the given id, and stats.
        //The race type will be either “Casual”, “Drag” or “Drift”.
        var raceFactory = new RaceFactory();
        var race = raceFactory.MakeRace(type, length, route, prizePool);

        if (race != null)
        {
            this.races.Add(id, race);
        }
        else
        {
            throw new ArgumentException("Open: race is null");
        }
    }
    public void Open(int id, string type, int length, string route, int prizePool, int extraParameter)
    {
        var race = RaceFactory.MakeRace(id, type, length, route, prizePool, extraParameter);

        races.Add(id, race);
    }