Appeals in probate proceedings, in contested election cases, and in actions for libel or slander by a person who holds any elective public office or a candidate for any such office alleged to have occurred during the course of an election campaign shall be given preference in hearing in the courts of appeal, and in the Supreme Court when transferred thereto. All these cases shall be placed on the calendar in the order of their date of issue, next after cases in which the people of the state are parties.