define set a 1 ---- get a ---- 1 get b ---- pebble: not found define set a 1 set a 2 ---- get a ---- 2 define set a 1 set a 2 del a ---- get a ---- pebble: not found define set a 1 set a 2 del a set a 3 ---- get a ---- 3 define merge a 1 merge a 2 merge a 3 ---- get a ---- 123 commit ---- define merge a 4 ---- get a ---- 1234 commit ---- define del a set a 5 ---- get a ---- 5 define del-range a b ---- get a ---- pebble: not found commit ---- define ---- get a ---- pebble: not found define merge b 1 merge b 2 del-range b c merge b 3 merge b 4 ---- get b ---- 34 commit ---- define ---- get b ---- 34