What is the test for a jury to determine whether a defendant was justified in using excessive force against an alleged aggressor?

Defendants also claim that they were entitled to use self-defense. Any force which is excessive, i.e., unreasonable under the circumstances, is not justified and the extent to which one may make resistance against an aggressor is a fact to be determined by a jury. (See People v. Moody (1943) 62 Cal.App.2d 18, 22, 143 P.2d 978.) Even assuming (which we do not think was true) that both defendants were entitled to use force to defend themselves against Palacios we believe that the jury could reasonably find the use of deadly force by the defendants to be excessive under the circumstances.