What is the test for a defendant to be found liable for the actions of his aider and abettor?

"[P]roof of aider and abettor liability requires proof in three distinct areas: (a) the direct perpetrator's actus reusa crime committed by the direct perpetrator, (b) the aider and abettor's mens reaknowledge of the direct perpetrator's unlawful intent and an intent to assist in achieving those unlawful ends, and (c) the aider and abettor's actus reusconduct by the aider and abettor that in fact assists the achievement of the crime." (People v. Perez (2005) 35 Cal.4th 1219, 1225 (Perez).)