4. Shirley is an actress under contract with Twentieth Century. Shirley agreed to perform the lead role in a musical to be filmed in Hollywood by Twentieth Century. At the last minute, Twentieth Century decided to scrap the musical and assigned its rights in Shirley to MGM. MGM was planning to film a western in Australia requiring Shirley to spend six months filming in Australia. Can Shirley successfully prevent this assignment? As part of your answer you should identify and explain the rule of law that applies and analyze its application to these facts.