private List<Inspector> valueListFromInspector(Inspector inspector){
        List<Inspector> inspectorList = new ArrayList<>();
        inspector.traverse((ArrayTraverser) (key, value) -> inspectorList.add(value));
        return inspectorList;
    }
Translates a list of grouping requests on JSON form to a list in the grouping language form
container-search/src/main/java/com/yahoo/search/query/SelectParser.java