United States v. Garcia-Sandobal, 703 F.3d 1278, 2013 WL 28255 (11th Cir. Jan. 3, 2013) (although defendant initially object[ed] to the characterization of his prior conviction as an aggravated felony, and purported to preserve a right to challenge the classification of his prior conviction at sentence, but later unequivocally pleaded guilty to a violation of 18 U.S.C. 1326(b)(2) and agreed that he had been removed following a conviction for an aggravated felony; Eleventh Circuit held that a defendant cannot plead guilty but preserve this challenge); see United States v. Bennett, 472 F.3d 825, 833 (11th Cir. 2006) (court explained that Bennett's guilty plea included an admission to his having three prior violent felony convictions, and explained that [t]his alone authorized the district court to sentence Bennett as an armed career criminal under 924(e).).