Intermediate Swift 3 Challenge - Property Observers

QUESTION: In the editor, I've created a UIViewController subclass, TemperatureController that contains a single property - temperature. Your task is to add a didSet property observer to temperature and set the view's background color depending on value of the temperature. For example, if the temperature is greater than 80, set the view's background color to UIColor.red. Similarly if the temperature is less than 40, set it to blue color, otherwise set it to green color. Note: For changing the view's background color, there's example code in viewDidLoad()

Hey! I seem to be stuck on this challenge and am not sure what I'm doing wrong or how to proceed - if someone could maybe steer me in the right direction or point out something im not seeing that would be a really big help, thanks!

class TemperatureController: UIViewController {
    var temperature: Double {
      didSet {
        if temperature > 80.0 {
          view.backgroundColor = UIColor.red
         } else if temperature < 40.0 {
          view.backgroundColor = UIColor.blue
         } else {
          view.backgroundColor = UIColor.green 
         }
       }

    init(temperature: Double) {
        self.temperature = temperature
        super.init()
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
    }
}