What is the test for a jury to convict defendants of conspiracy to commit second degree murder?

The error here in instructing on conspiracy to commit second degree murder was nonetheless harmless beyond a reasonable doubt. Based on the remaining instructions, the prosecutors argument, and the jury verdicts, we conclude that the "jury necessarily found the defendants guilty of conspiracy to commit murder on a proper theory, i.e., based on express malice or intent to kill." ( People v. Swain (1996) 12 Cal.4th 593, 607, 49 Cal.Rptr.2d 390, 909 P.2d 994 ( Swain ).)