NSBundle object with which the specified class is associated.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
NSBundle object that dynamically loaded
a (a loadable bundle), the
NSBundle object for the framework in which
a is defined, or the main bundle object if
a was not dynamically loaded or is not defined in a framework.
This method creates and returns a new
NSBundle object if there is no existing bundle associated with
a. Otherwise, the existing instance is returned.