What is the test for a medical marijuana defense?

Appellant contends the trial court erred in failing to sua sponte instruct the jury on the medical marijuana defense. We disagree. The trial court must instruct sua sponte on a defense "'only if it appears that the defendant is relying on such a defense, or if there is substantial evidence supportive of such a defense and the defense is not inconsistent with the defendant's theory of the case.'" (People v. Barton (1995) 12 Cal.4th 186, 195, quoting People v. Sedeno (1974) 10 Cal.3d 703, 716.)