Does a sentence of life without possibility of parole constitute cruel and unusual punishment?

On the other hand, the court in People v. Sullivan (2007) 151 Cal.App.4th 524, 572, held that the fact a defendant may not be able to serve the entirety of his or her sentence does not in itself make the punishment inappropriate. In practical effect a defendant is in the same position as one sentenced to life without possibility of parole and the latter sentence has been held in appropriate cases not to violate the prohibition against cruel and unusual punishment under either the federal or California Constitution. (Id. at p. 572.)