Cal. CCP § 607a

In every case which is being tried before the court with a jury, it shall be the duty of counsel for the respective parties, before the first witness is sworn, to deliver to the judge presiding at the trial and serve upon opposing counsel, all proposed instructions to the jury covering the law as disclosed by the pleadings. Thereafter, and before the commencement of the argument, counsel may deliver to such judge, and serve upon opposing counsel, additional proposed instructions to the jury upon questions of law developed by the evidence and not disclosed by the pleadings. All proposed instructions shall be typewritten, each on a separate sheet of paper. Before the commencement of the argument, the court, on request of counsel, must: (1) decide whether to give, refuse, or modify the proposed instructions; (2) decide which instructions shall be given in addition to those proposed, if any; and (3) advise counsel of all instructions to be given. However, if, during the argument, issues are raised which have not been covered by instructions given or refused, the court may, on request of counsel, give additional instructions on the subject matter thereof.