If that all worked for you, let's take another step and talk about why you want to return null. It's a pain for the caller to have to test and it's often unclear exactly what we're trying to tell somebody when we return null. We have ways of making life easier for the caller in almost any program.
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi