What is the test for a de novo review of the findings of the Court of Appeal of a finding that a plaintiff was sexually assaulted during her pregnancy?

Our review of the trial court's findings presents mixed questions of law and fact. (Ali v. City of Los Angeles (1999) 77 Cal.App.4th 246, 250.) "Mixed questions of law and fact involve three steps: (1) the determination of the historical facts--what happened; (2) selection of the applicable legal principles; and (3) application of those legal principles to the facts. The first step involves factual questions exclusively for the trial court to determine; these are subject to substantial evidence review; the appellate court must view the evidence in the light most favorable to the judgment and the findings, express or implied, of the trial court. [Citations.] . . . Only the second and third steps involve questions of law for our de novo review." (Ibid.)