Parties.

When declaratory relief is sought, all persons may be made parties who have or claim any interest which would be affected by the declaration. No declaration shall prejudice the rights of persons not parties to the proceedings. In any proceeding concerning the validity of a county or municipal charter, ordinance, or franchise, such county or municipality shall be made a party and shall be entitled to be heard. If the statute, charter, ordinance, or franchise is alleged to be unconstitutional, the Attorney General or the state attorney of the judicial circuit in which the action is pending shall be served with a copy of the complaint and be entitled to be heard.