Suppose I have String like :
var abc : NSString = \"ABC\"
and I want to check that it is nil or not and for that I try :
if
if (MyUnknownClassOrType is nil) {
println("No class or object to see here")
}
Apple also recommends that you use this to check for depreciated and removed classes from previous frameworks.
Here's an exact quote from a developer at Apple:
Yes. If the currently running OS doesn’t implement the class then the class method will return nil.
Hope this helps :)