Cal. Pub. Util. Code § 1758

(a) The commission and each party to the action or proceeding before the commission may appear in the review proceeding.
Upon the hearing the Supreme Court or court of appeal shall enter judgment either affirming or setting aside the order or decision of the commission.
(b) The provisions of the Code of Civil Procedure relating to writs of review shall, so far as applicable and not in conflict with this part, apply to proceedings instituted in the Supreme Court or court of appeal under this article.
(c) Under this article, the Supreme Court may review decisions of the court of appeal in the manner provided for other civil actions.
(d) The Supreme Court shall grant expedited consideration to any party or commission petition alleging that the court of appeal has assumed jurisdiction to review a commission decision pertaining solely to water corporations over which the court of appeal has no jurisdiction.