static void Main(string[] args)
        {
            Console.WriteLine("Welcome to your inventory! 'quit' or 'q' to exit");
            InventoryDatabase   DB           = new InventoryDatabase();
            OwnerConsoleUI      ownerUI      = new OwnerConsoleUI(DB.Owners);
            PossessionConsoleUI possessionUI = new PossessionConsoleUI(DB.Possessions, DB.Owners);
            string input = "";

            while (input.ToLower() != "quit" && input.ToLower() != "q")
            {
                PrintOptions();
                input = Utility.ReadAndCheckForQuit();
                if (input.ToLower() == "q" || input.ToLower() == "quit")
                {
                    continue;
                }
                int  selection;
                bool goodIn = int.TryParse(input, out selection);
                if (!goodIn || !(selection < MAX_NUM + 1 && selection > 0))
                {
                    Console.WriteLine($"Please enter a number 1-{MAX_NUM}");
                    continue;
                }
                HandleSelection(selection, ownerUI, possessionUI);
            }
        }
        private static void HandleSelection(int selection, OwnerConsoleUI ownerUI, PossessionConsoleUI possessionUI)
        {
            switch (selection)
            {
            case 1:  ownerUI.SeePeople();                   break;

            case 2:  ownerUI.SeeCats();                     break;

            case 3:  ownerUI.AddOwner(OwnerTypes.Human);    break;

            case 4:  ownerUI.AddOwner(OwnerTypes.Cat);      break;

            case 5:  ownerUI.UpdateOwner(OwnerTypes.Human); break;

            case 6:  ownerUI.UpdateOwner(OwnerTypes.Cat);   break;

            case 7:  ownerUI.DeleteOwner();                 break;

            case 8:  possessionUI.SeeAllStuff();            break;

            case 9:  possessionUI.SeeAllStuffByOwner();     break;

            case 10: possessionUI.SeeAllStuffByOwnerType(); break;

            case 11: possessionUI.ChangeOwners();           break;

            case 12: possessionUI.InstallUninstallStuff();  break;

            case 13: possessionUI.UpdateStuff();            break;

            case 14: possessionUI.DeleteStuff();            break;

            case 15: possessionUI.AddStuff();               break;

            default: throw new ArgumentException();
            }
            Console.WriteLine("============================");
        }