build a.SET.1:A aa.SET.2:AA c.SET.3:C d.SET.4:D ---- iter seek-prefix-ge a next next ---- :A :AA . iter seek-prefix-ge aa next ---- :AA . iter seek-prefix-ge aa prev ---- :AA . iter seek-prefix-ge c prev ---- :C . iter seek-prefix-ge b ---- . iter seek-prefix-ge c next ---- :C . iter seek-prefix-ge d next ---- :D . iter seek-prefix-ge e ---- . iter seek-prefix-ge c seek-prefix-ge d seek-prefix-ge e ---- :C :D . iter seek-prefix-ge c next seek-prefix-ge a next next ---- :C . :A :AA . iter seek-prefix-ge aa next seek-prefix-ge a next next seek-prefix-ge c next ---- :AA . :A :AA . :C . iter seek-prefix-ge c next seek-prefix-ge aa next seek-prefix-ge a next next ---- :C . :AA . :A :AA . iter seek-prefix-ge a next next ---- :A :AA . iter seek-prefix-ge a next prev prev ---- :A :AA :A . iter seek-prefix-ge a prev ---- :A . iter seek-prefix-ge a seek-ge a next next next next ---- :A :A :AA :C :D . iter seek-prefix-ge a seek-ge aa next next next ---- :A :AA :C :D . iter seek-prefix-ge aa seek-ge c next next ---- :AA :C :D . iter seek-prefix-ge aa seek-lt c next next next ---- :AA :AA :C :D . iter seek-prefix-ge aa seek-lt c prev prev ---- :AA :AA :A . iter seek-lt c seek-prefix-ge aa prev ---- :AA :AA . iter seek-lt c seek-prefix-ge a next next ---- :AA :A :AA . iter seek-ge aa seek-prefix-ge a next next ---- :AA :A :AA . iter seek-prefix-ge 1 ---- . get a aa f d c ---- A AA D C iter seek-prefix-ge a false seek-prefix-ge a true seek-prefix-ge aa true seek-prefix-ge d true seek-prefix-ge c false ---- :A :A :AA :D :C