Dana Johnson appeals the 7-month prison sentence that the district court 1 imposed after revoking his supervised release. We dismiss the appeal as moot, because he was released from custody on October 17, 2006. See Spencer v. Kemna, 523 U.S. 1, 6, 18, 118 S.Ct. 978, 140 L.Ed.2d 43 (1998) (declaring moot challenge to allegedly erroneous parole revocation because defendant had already served entire sentence).

Accordingly, we dismiss this appeal as moot.