append a 10
append a 20
append a 30
append a 40
append b 5
append b 15
append b 25
prepend a 4
prepend a -5
prepend b a
prepend a b
remove a 3
remove b 3
remove a 2 10
insert a 0 3
insert a 1 4
insert a 0 9
insert a 2 10
clear b
clear a
append a 10
append a 20
append a 30
append a 40
append a 50
append a 60
append a 70
append a 80
slice a 2 4 b
slice a 0 6 b
slice b 1 4 a