Swift 5 requires the ViewController to adopt NSFontChanging

[ganeshh123]

Firstly, thanks so much for making this, I have no idea how you figured this out I couldn't find any decent documentation for this anywhere.

The current example works for up to Swift 4, but shows an error in Swift 5:
Method does not override any method from its superclass

To fix this, the ViewController needs to adopt the NSFontChanging protocol:

Then in the implementation, the override needs to be removed and Any? needs to be updated to NSFontManager?:

func changeFont(_ sender: NSFontManager?){}

The demo will then work correctly:

Could you please update the README to reflect this?