docs: private HashMap<String, String[]>[] expandedQueryVariables(
        HashMap<String, String[]> queryVariables) {
      ArrayList<HashMap<String, String[]>> result = new ArrayList<>();
      Set<String> keys = queryVariables.keySet();
      generatePermutationsQueryVariables(result, keys, queryVariables);
      return result.toArray(new HashMap[result.size()]);
    }