Yes that works if you already know what you’ll be putting inside of it, in this case you can even take a NSArray instead of <?>, as using arrayWithObjects() will return an NSArray with the type of the objects you passed as parameters 
Yes that works if you already know what you’ll be putting inside of it, in this case you can even take a NSArray instead of <?>, as using arrayWithObjects() will return an NSArray with the type of the objects you passed as parameters