the error was harmless, i.e., that the error did not affect the district court’s selection of the sentence imposed. Williams v. United States, 503 U.S. 193, 203, 112 S.Ct. 1112, 1120-21, 117 L.Ed.2d 341 (1992). Under Williams, “in order to avoid a remand we must conclude that the district court has not relied on the improper factor, at least not in a but-for outcome-determinative sense.” United States v. Jones, 983 F.2d 1425, 1429 (7th Cir.1993). A reviewing court can be certain that an error in sentencing is harmless where the district court gives detailed reasons and findings that make clear that the court was not wholly relying exclusively on the improper material. United States v. Mount, 966 F.2d 262, 265 (7th Cir.1992); cf. United States v. Dawson, 1 F.3d 457, 465 (7th Cir.1993) (<HOLDING>). Thus, an appellate court can affirm the
holding that district courts error was not harmless because the court relied on an improper factor in imposing an upward departure holding harmless any error in departing upward under ussg  4a13 where district court alternatively imposed reasonable sentence as an upward variance holding that the governments representations to the court that it was not seeking an upward departure suggested it had not breached the plea agreement holding that the district courts error in calculating the amount of drugs at issue was harmless because the error had no impact on the defendants sentence holding that the requisite notice must specifically identify the ground on which the district court is contemplating an upward departure