Returns the value associated with a given key.
- iOS 6.0+
- macOS 10.8+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
- watchOS 2.0+
The key for which to return the corresponding value.
The value associated with
nil if no value is associated with
This method has the same behavior as the
You shouldn’t need to call this method directly. Instead, this method is called when accessing an object by key using subscripting.