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