What is the test for abuse of a district court's decision refusing to sever a defendant's case from those of his co-defendants?

We review for abuse of discretion a district court's decision refusing to sever a defendant's case from those of his co-defendants. United States v. Sherlock, 865 F.2d 1069, 1078 (9th Cir.1989). In general, a defendant is entitled to a separate trial if he will present a defense that is completely antagonistic to a co-defendant's. Id. at 1081. A defense is completely antagonistic only in those cases where the defenses of the co-defendants are "irreconcilable and mutually exclusive." Id.