Конструктор singleton`а

public class Manager : Logic.IManager
    {
        private IExecutor executor;
        private List<IMemory> memoriesList;

        private static Manager instance;
        public static Manager GetInstance(List<IMemory> memList, IExecutor executor)
        {
            if (instance == null)
            {
                instance = new Manager(memList, executor);
            }
            return instance;
        }

        private Manager(List<IMemory> memList, IExecutor executor)
        {
            instance = new Manager();
            instance.memoriesList = memList;
            instance.executor = executor;
            foreach (IMemory mem in memList)
            {
                mem.Timer.CounterFires += new EventHandler(Timer_CounterFires);
                mem.StartTimer();
            }
        }

        private Manager()
        {
           
        }