[bugfix] remove confirmable_set_at
[bugfix] remove confirmable_set_at

ddmck/Empirical-Core,empirical-org/Quill-Lessons,empirical-org/Quill-Lessons,empirical-org/Empirical-Core,empirical-org/Empirical-Core,empirical-org/Quill-Lessons,empirical-org/Empirical-Core,empirical-org/Quill-Lessons,empirical-org/Empirical-Core,empirical-org/Empirical-Core,ddmck/Empirical-Core,ddmck/Empirical-Core,empirical-org/Empirical-Core,empirical-org/Empirical-Core,ddmck/Empirical-Core