What is the test for admitting a defendant who has a prior conviction for the same or substantially similar crime?

" '... A special and even more difficult problem arises when the prior conviction is for the same or substantially similar conduct for which the accused is on trial. Where multiple convictions of various kinds can be shown, strong reasons arise for [174 Cal.App.3d 182] excluding those which are for the same crime because of the inevitable pressure on lay jurors to believe "if he did it before he probably did so this time." As a general guide, those convictions which are for the same crime should be admitted sparingly....' " (People v. Beagle, supra, 6 Cal.3d at p. 453, 99 Cal.Rptr. 313, 492 P.2d 1.)