What is the test for a death sentence based on a multiple-murder special circumstance?

Defendant asserts that the multiple-murder special circumstance, which formed the basis for his death sentence, is "particularly deficient in terms of a narrowing function" for two reasons. First he claims it encompasses an "overly broad class of defendants of disparate and varying culpability." To the contrary, the multiple-murder special circumstance focuses on a narrow group of killers: only those who have murdered more than one person. Second, defendant asserts the multiple-murder special circumstance improperly focuses on the nature of the act committed rather than the defendant's mental state. We are not persuaded. One who is mentally prepared to commit repeated acts of murder, or to commit a murderous act that results in the death of two or more persons, is more dangerous to society and more deserving of the ultimate punishment than one who has killed once. (See generally People v. Coddington, supra, 23 Cal.4th at p. 656, 97 Cal.Rptr.2d 528, 2 P.3d 1081 [holding multiple-murder special circumstance constitutional].)