What is the current state of the law on the instruction of a jury in a second degree murder case?

The Dewberry court held: "The proposed instruction should have been given. It went directly to the defense of reasonable doubt of defendant's guilt of second degree murder; it was clearly responsive to an issue raised by the evidence [citations]; and it was essential to cure the misleading effect of its absence in the light of the other instructions given. Under these circumstances there exists 'such an equal balance of reasonable probabilities as to leave the court in serious doubt as to whether the error has affected the result,' and accordingly the error is prejudicial. [Citation.]" People v. Dewberry, supra, 51 Cal.2d at pp. 557-558.)