United States v. Guerrero-Velasquez, 434 F.3d 1193, 1194 (9th Cir. 2006) (a guilty plea is an admission of the facts charged in the indictment, and an Alford plea, in which the defendant enters a guilty plea while maintaining his innocence, is nevertheless a guilty plea under Taylor v. United States, 495 U.S. 575, 110 S. Ct. 2143, 109 L. Ed. 2d 607 (1990)).