The defendant in People v. Czahara (1988) ) 203 Cal. App. 3d 1468 [250 Cal. Rptr. 836 was charged with attempted murder. He contended that the trial court had erroneously excluded psychiatric testimony that he had acted in the heat of passion and that his reaction was objectively reasonable. The appellate court held that, because the psychiatric testimony would have "completely negated malice aforethought," the evidence was inadmissible under section 29. (People v. Czahara, supra, 203 Cal. App. 3d at p. 1477.)