In re Douglas, 200 Cal.App.4th 236, 132 Cal.Rptr.3d 582, 590 (4th Dist. Oct. 27, 2011) (petitioner is not in custody, for purposes of attacking a 1997 conviction, even though he is in current constructive custody as a result of later convictions for failure to register as a sex offender based on the registration requirement imposed as a result of the 1997 conviction).