Is a federal district court's failure to hold an evidentiary hearing on use immunity constitute reversible error?

Whether the district court's failure to hold an evidentiary hearing on use immunity constitutes reversible error is a mixed question of law and fact, which we review de novo. See United States v. Young, 86 F.3d 944, 947 (9th Cir.1996). "A criminal defendant is not entitled to compel the government to grant immunity to a witness." Id. There is an exception to this rule where the defendant shows that the proposed testimony was relevant and that the government intentionally distorted the judicial fact-finding process. See id.