Can a peremptory challenge be made to the judge assigned to a judge for all purposes?

A peremptory challenge may generally be made at any time prior to commencement of the trial or hearing. (Los Angeles County Dept. of Pub. Social Services v. Superior Court (1977) 69 Cal.App.3d 407, 412, 138 [6 Cal.App.4th 155] Cal.Rptr. 43.) However, section 170.6 provides: "[i]f directed to the trial of a cause which has been assigned to a judge for all purposes, the motion shall be made to the assigned judge or to the presiding judge by a party within 10 days after notice of the all purpose assignment...." ( 170.6, subd. (2).)