but contends his situation falls within an exception to the general rule because the court misinterpreted the guidelines as prohibiting a departure. See, e.g., United States v. Fortier, 180 F.3d 1217, 1231 (10th Cir.1999). Note 9 to § 2D1.1 states that upward departures may be warranted for trafficking drugs of unusually high purity, although methamphetamine is specifically excluded. Mr. Arreola-Najera argues that the opposite consideration should also apply even if the drug involved is methamphetamine; i.e., that a downward departure may be warranted for drugs of particularly low purity, which he contends was the case here. We note that the circuits are split on whether note 9 permits a downward departure. Compare United States v. Mendoza, 121 F.3d 510, 513, 515 (9th Cir.1997) (<HOLDING>); with United States v. Beltran, 122 F.3d 1156,
holding that district court did not have authority to depart downward under note 9 based on low purity of methamphetamine involved in case holding that the district courts denial of a downward departure was an exercise of discretion and therefore not reviewable holding that a defendants substance abuse or addiction does not justify a downward departure holding that note 9 did not authorize downward departure based on drug purity holding that note 9 does not preclude downward departure where defendant had no control over or knowledge of the highlevel purity of methamphetamine involved