What is the test for abuse of the sentencing guidelines in the Court of Appeal?

We review for abuse of discretion the district court's decision to depart from the sentencing ranges in the guidelines. Koon v. United States, --- U.S. ----, ----, ---- - ----, 116 S.Ct. 2035, 2043, 2046-48, 135 L.Ed.2d 392 (1996). Courts of appeals are required to " 'give due deference to the district court's application of the guidelines to the facts.' " Id. at ----, 116 S.Ct. at 2046 (quoting 18 U.S.C. 3742). "[E]xcept to the extent specifically directed by statute, it is not the role of an appellate court to substitute its judgment for that of the sentencing court as to the appropriateness of a particular sentence." Id. (quotations omitted).