Decrees affirmed. This is a "bill for declaratory judgment and bill for accounting" brought by the Attorney General in behalf of the Metropolitan District Commission against a public utility corporation of Massachusetts with respect to rates charged by the defendant for electric street lighting. The plaintiff appealed from an interlocutory decree sustaining the defendant's demurrer to the bill of complaint, and from a final decree dismissing the bill. We shall not analyze the grounds of demurrer, because under G.L.c. 231A, § 8, "When declaratory relief is sought, all persons shall be made parties who have or claim any interest which would be affected by the declaration, and no declaration shall prejudice the rights of persons not parties to the proceeding." The Department of Public Utilities, which has not been made a party, has an interest which would be affected. Harvey Payne, Inc. v. Slate Co. 342 Mass. 368, 370. We are satisfied that any declaration which we might make would not end the controversy. Id. See G.L.c. 231A, § 3. This is not an appropriate case to state views not necessary to the decision, as in Wellesley College v. Attorney Gen. 313 Mass. 722, 731.