   }
   
   let title: String
+  let subtitle: String?
   let websiteURL: URL?
   let rgbColor: API.RGBColor
   let required: Bool?

  public func title(forModeIdentifier mode: String) -> String? {
    return response?.modes?[mode]?.title
  }
  
  /// - Parameter mode: The mode identifier for which you want the official website URL
  /// - Returns: The URL as defined by the server
  @objc

struct ModeDetails: Codable {
  private enum CodingKeys: String, CodingKey {
    case title
    case subtitle
    case websiteURL = "URL"
    case rgbColor = "color"
    case required
