What is the test on appeal for establishing that Prior 3 is a Serious Felony?

" 'When, as here, a defendant challenges on appeal the sufficiency of the evidence to sustain the trial court's finding that the prosecution has proven all elements of the enhancement [based on a conviction in another jurisdiction], we must determine whether substantial evidence supports that finding. The test on appeal is . . . whether a reasonable trier of fact could have found that the prosecution sustained its burden of proving the enhancement beyond a reasonable doubt.' [Citation.] In making this determination, we review the record in the light most favorable to the trial court's findings." (People v. Rodriguez (2004) 122 Cal.App.4th 121, 129.)

C. The Prosecution Did Not Establish Prior 3 is a Serious Felony Under California Law