What is the test for determining whether a defendant has been deprived of counsel at sentencing because of a structural error?

³ We have held the third prong is similar to the harmless-error analysis and is satisfied when, as here, the alleged error is structural. See United States v. Collins, 684 F.3d 873, 881 (9th Cir.2012) ([I]f the plain error was a structural one, the existence of prejudice is generally presumed.); Robinson v. Ignacio, 360 F.3d 1044, 1061 (9th Cir.2004) (explaining the deprivation of counsel at sentencing is structural error).

³ We have held the third prong is similar to the harmless-error analysis and is satisfied when, as here, the alleged error is structural. See United States v. Collins, 684 F.3d 873, 881 (9th Cir.2012) ([I]f the plain error was a structural one, the existence of prejudice is generally presumed.); Robinson v. Ignacio, 360 F.3d 1044, 1061 (9th Cir.2004) (explaining the deprivation of counsel at sentencing is structural error).