What is the legal test for a motion of appeal against a finding of not guilty of a charge of sexual assault brought before the Court of Appeal?

One other principle should be brought to mind before we return to our survey of the procedural procession. It is that: 'The power of a trial or appellate court to order a new trial on fewer than all the issues is generally recognized (citing authorities). * * * Such retrials should be granted, however, only if it is clear that no injustice will result. (Citing authorities.) (Leipert v. Honold (1952) 39 Cal.2d 462, 466, 247 P.2d 324, 327.)