/// <summary>
 /// User buys a costly item but inserts less money at first
 /// </summary>
 /// <param name="machine"></param>
 private static void Scenario_2(IVendingMachineClient machine)
 {
     Console.WriteLine("**********Scenario 2**************\n");
     machine.SelectProduct("Tango");
     machine.InsertCoin(50);
     Console.WriteLine("\n**********END**************");
 }
 /// <summary>
 /// Continuing from Scenario 2, user inserts rest of the money and gets 7P back
 /// Note that the user enters in 20Ps.
 /// </summary>
 /// <param name="machine"></param>
 private static void Scenario_3(IVendingMachineClient machine)
 {
     Console.WriteLine("\n**********Scenario 3**************\n");
     Console.WriteLine("...continuing from Scenario 2\n");
     machine.InsertCoin(20);
     machine.InsertCoin(20);
     machine.InsertCoin(20);
     machine.InsertCoin(20);
     machine.InsertCoin(20);
     machine.InsertCoin(20);
     Console.WriteLine("\n**********END**************");
 }