Cal. Pen. Code § 1161
When there is a verdict of conviction, in which it appears to the Court that the jury have mistaken the law, the Court may explain the reason for that opinion and direct the jury to reconsider their verdict, and if, after the reconsideration, they return the same verdict, it must be entered; but when there is a verdict of acquittal, the Court cannot require the jury to reconsider it. If the jury render a verdict which is neither general nor special, the Court may direct them to reconsider it, and it cannot be recorded until it is rendered in some form from which it can be clearly understood that the intent of the jury is either to render a general verdict or to find the facts specially and to leave the judgment to the Court.
Ca. Pen. Code § 1161