I’m working through an Apple WWDC 2019 video about fonts, which includes this sample code for registering (enabling) fonts with the OS :

static func registerFamilies(_ names: [FontFamily], _ registrationHandler: 
    (([Error], Bool) -> Bool)?) {
    let fontURLs = names.flatMap({ $0.urls })
    CTFontManagerRegisterFontURLs(fontURLs as CFArray, .persistent, true) {
        (errors: CFArray, done: Bool) -> Bool in
        return processHandler(errors: errors, done: done, registrationHandler) 
    }
}

However, this flags several errors:

• Cannot find type “FontFamily” in scope;
• Static methods must only be declared on a type
• Cannot find processHandler in scope.

A static function affects all instances of a class, so presumably the absence of a defined class “FontFamily” is causing two errors. But it’s unclear to me what that type should be.

Presumably I have to create my own processHandler function that does… something.

I’ve imported CoreText and Foundation. What am I missing?