PHP Test if Class Instance exists in an array Instances
<p>I've got a Collection of closely related Objects. Before I add an Object to the collection, I want to check the class instance to make sure it's OK.</p>

<p>Normally, I like all my objects in a collection to have a similar baseClass OR interface so I can use type hinting but in this case, the objects aren't like that.</p>

<p>I like the way <code>instanceof</code> works. I don't want to have to manage a list of namespaces.</p>
