To use the location service, we need to instruct iOS that our app is using it.

To do this, we must add the NSLocationAlwaysUsageDescription key with a string, for example, "This application requires location services to get the weather of your current location." in Info.plist.

Then, we add a new property to PrettyWeatherViewController:

    private var locationDatastore: LocationDatastore?

Next, we change the viewWillAppear function:

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)
        locationDatastore = LocationDatastore() { [weak self] location in
            FlickrDatastore().retrieveImageAtLat(location.lat, lon: location.lon){ image in
                self?.render(image)
                return
            }
        }
    }

Our simple wrapper around LocationManager basically calls the provided closure...