The Swift programming language allows a programmer to extend types, even existing built in types such as Int. Here, I've used the func keyword to declare a new function called carefullyDividedBy, which takes a second integer, which represents the denominator and optionally returns a result. If the denominator is zero, we return the Optional none, representing the lack of a value. If the denominator is anything other than zero, we return something, namely the original number divided by the denominator.