What is the standard of review in the context of a summons issued by the Department of Justice?

The second case presented by appellants, United States v. Blackman, 72 F.3d 1418, 1422 (9th Cir.1995), supports our analysis in the present case. It indicates that a requisite element of the Government's prima facie case for validating a summons is that "the inquiry is relevant" to a legitimate investigative purpose. Id., at 1424. It then restates the applicable standard of review to be clear error. Id. As we have detailed above, the district judge determined the Government's inquiry not to be relevant to its legitimate investigation and we do not find that she clearly erred in making this determination.