What is the current state of the law on penalty and punishment in a criminal case?

"It is settled that in the trial of a criminal case the trier of fact is not to be concerned with the question of penalty, punishment or disposition in arriving at a verdict as to guilt or innocence." (People v. Allen (1973) 29 Cal.App.3d 932, 936, 106 Cal.Rptr. 43, fn. omitted.) CALJIC No. 17.42, which was read to defendant's jury, advised them not to discuss the subject of penalty or punishment in arriving at their verdict. "Without that advice a jury may permit their consideration of guilt to be deflected by a dread of seeing the accused suffer the statutory punishment." (People v. Shannon (1956) 147 Cal.App.2d 300, 306, 305 P.2d 101.)