How does section 1054.9 of the California Penal Code apply to defendants serving a sentence of life without possibility of parole?

Defendant contends that Penal Code section 1054.9 applies to defendants serving prison terms which are the functional equivalent of a sentence of life without the possibility of parole, where parole eligibility falls outside of a defendant's natural lifespan. In making this argument, he relies on cases considering whether de facto life sentences for minors constitute cruel and unusual punishment, and cases interpreting Proposition 47 to apply to unenumerated theft offenses. (See, e.g., People v. Caballero (2012) 55 Cal.4th 262, 268 [finding that sentencing a juvenile offender for a nonhomicide offense to a term of years with a parole eligibility date falling outside the offender's natural life expectancy constitutes cruel and unusual punishment]; People v. Martinez (2018) 4 Cal.5th 647, 657 [discussing breadth of Prop. 47].) These cases have no application here.