Initializes and returns an empty document object.
- macOS 10.0+
This initializer (the designated initializer) is invoked by each of the other
NSDocument initialization methods.
You can override this method to perform initialization that must be done both when creating new empty documents and when opening existing documents. Your override must invoke
super to initialize private
NSDocument instance variables. It must never return
nil. If an error can occur during object initialization, check for the error in an override of
init, because those methods can return