sack
Read and write sacks.
Synopsis
sack(traversal)
Description
The sack() step is a map/sideEffect step that is used to read or write sacks, local data structures that traversers use.
Examples
g.withSack(0).V().
  has("person", "name", "John Doe").
  outE("reviewed").
    sack(sum).by("stars").
  outV().
  sack()