Raises an exception.
- iOS 5.0+
- macOS 10.7+
- Mac Catalyst 13.0+
- tvOS 9.0+
- watchOS 2.0+
The object to remove as an observer.
A key-path, relative to the set, for which observer is registered to receive KVO change notifications. This value must not be nil.
NSOrdered objects are not observable, so this method raises an exception when invoked on an
NSOrdered object. Instead of observing an ordered set, observe the to-many relationship for which the ordered set is the collection of related objects.