nasaImage()
    .done { image in
       self.apodImage.image = image
    }.catch { (error) in
        let alert = UIAlertController(title: "Error",
                                      message:"<<Error message>>",
                                      preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK",
                                      style: .default,
                                      handler: nil))

        self.present(alert, animated: true, completion: nil)
    }