docs: public void newGroup() {
          // create parent
          QueryCriteria newCriteriaGroupParent = new QueryCriteria(this.union);
          addCriteria(newCriteriaGroupParent);
  
          //  add parent to parent stack
          ancestry.push(currentParent);
          currentParent = newCriteriaGroupParent;
  
          // set group criteria list to new list
          currentCriteria = newCriteriaGroupParent.getCriteria();
      }