Harry executes a will, which leaves all of his property to his wife, Wilma. If Wilma predeceases, Harry's estate shall pass to his children and to Wilma's children. Wilma executes a will, which leaves everything to Harry, but if Harry predeceases, her estate shall pass to Harry's children and to Wilma's children.Harry later dies. Wilma takes Harry's entire estate. She then, promptly, executes a new will leaving everything to her children only. Is Wilma's will valid?