public void ReceiveContents(Jewels safeContents)
 {
     returnedContents = safeContents;
     Console.WriteLine("Thank you for returning my jewels! " + safeContents.Sparkle ());
 }
 override public void ReturnContents(Jewels safeContents,Owner owner)
 {
     stolenJewels = safeContents;
     Console.WriteLine("I'm stealing the contents!" + stolenJewels.Sparkle());
 }