Is a defendant entitled to a jury instruction on any affirmative defense for which the record contains substantial evidence?

A defendant has a right to have the trial court give a jury instruction on any affirmative defense for which the record contains substantial evidence. (People v. Salas (2006) 37 Cal.4th 967, 982.) Substantial evidence is defined as that which is sufficient for a reasonable jury to find in favor of the defendant. (Ibid.) However, a trial court has no duty to instruct if the defense is inconsistent with the defendant's theory of the case. (Ibid.) "In determining whether the evidence is sufficient to warrant a jury instruction, the trial court does not determine the credibility of the defense evidence, but only whether 'there was evidence which, if believed by the jury, was sufficient to raise a reasonable doubt ....' [Citations.]" (Id. at pp. 982-983.)