What is the test for a reversal of a finding that a defendant waived his right to a jury trial?

Appellant contends he is entitled to a reversal because he never waived his right to a jury trial. Appellant relies on People v. Holmes [111 Cal.App.3d 979] (1960) 54 Cal.2d 442, 5 Cal.Rptr. 871, 353 P.2d 583, holding that a waiver of the right to a trial by jury must be expressed and will not be implied. Appellant also relies on People v. Kemick (1971) 17 Cal.App.3d 419, 94 Cal.Rptr. 835. The case at bench is distinguishable from Holmes and Kemick.