This is an XML Node operation to return an XML node under a node or create one if it does not exist. Probably commandnode under the first of your nodes shells.
Groovy , "", . ( ) , , DSL.
( ) JobDSL, , , NodeEnhancement, JavaDoc:
/**
Add div and leftShift operators to Node.
div - Will return the first child that matches name, and if it doesn't exists, it creates
...
**/