Checking state of NSButton Checkbox on Xcode for macOS apps swift 3

I have an NSButton Checkbox on Xcode using Swift 3 for making macOS applications. I'm trying to check the state (whether its on or off). Some options I have found, such as : if ([Switch1 state] == NSOnState) { //CODE} When I do this, it tells me to inout a comma after "Switch 1". Is this right, or is this version of code too old for Swift 3?

`@IBOutlet weak var Switch1: NSButton!
 override func viewDidLoad() {
    super.viewDidLoad()
    if ([Switch1 state] == NSOnState) {
        print("On")
    }  
  }`