Can a jury reverse a finding that a defendant guilty only of manslaughter be found guilty of a lesser charge?

As stated in People v. Powell, 34 Cal.2d 196, 205-206, 208 P.2d 974, 980, 'It cannot be doubted that a trier of fact has and often exercises the power, because of obvious extralegal factors or for no apparent reason, to find a defendant guilty of a lesser degree or class of crime than that shown by the evidence. Furthermore, even if it be assumed that the trier of fact erred here when he found defendant guilty only of manslaughter, defendant cannot invoke reversal on an error which is favorable to him. [Citations.] An appellant is precluded from complaining that he was convicted of a lesser offense than the one of which he is guilty according to undisputed evidence, or according to that view of the evidence which, it indisputably appears, the trier of fact accepted. [Citations.]'

Even if we assume that the court erred in not giving a full explanation of its answer to the query by the jury, there remains the question of whether the character and effect of that error were such as to require a reversal under the circumstances, having due regard to the terms of section [213 Cal.App.2d 778] 4 1/2 of article VI of the Constitution. We are of the opinion that it is not reasonably probable that a result more favorable to defendants or either of them would have been reached in the absence of the error complained of. If anything, the error resulted in a finding by the jury more favorable to one defendant than the law and the evidence warranted. It had no effect whatever on the other defendant, and consequently under no consideration would warrant a reversal. (People v. Watson, 46 Cal.2d 818, 836, 299 P.2d 243.)