How to randomly print a word in an iOS app - swift : I have been trying to create an app that randomly prints a new word after a certain amount of time, i.e five seconds.

    @IBOutlet weak var InspireLabel: UILabel!
    func randomText() -> String {
        if theValue > 5 {
        let words = ["Place", "Cat", "House"]
    return words[Int(arc4random_uniform(UInt32(words.count)))]
        }
    }

this is all the code I have right now. InspireLabel is the label which needs to change to the word. 'theValue' is the time passed. I keep getting a 'Missing return in a function expected to return 'String' error which stops me from running the code.