What is the test for invalidating a life sentence for a convicted rapist?

court must examine the circumstances of the offense, including its motive, the extent of the defendant's involvement in the crime, the manner in which the crime was committed, and the consequences of the defendant's acts. The court must also consider the personal characteristics of the defendant, including age, prior criminality, and mental capabilities. (People v. Dillon, supra , 34 Cal.3d at p. 479 [194 Cal.Rptr. 390, 668 P.2d 697].) If the court concludes that the penalty imposed is grossly disproportionate to the defendant's individual culpability (ibid. ), or, stated another way, that the punishment " shocks the conscience and offends fundamental notions of human dignity " ' [citation], the court must invalidate the sentence as unconstitutional."