docs: protected /*@pure@*/ int rangeSingle(/*@non_null@*/String singleSelection) {
  
          String single = singleSelection.trim();
          if (single.toLowerCase().equals("first")) {
              return 0;
          }
          if (single.toLowerCase().equals("last") || single.toLowerCase().equals("-1")) {
              return -1;
          }
          int index = Integer.parseInt(single);
          if (index >= 1) { //Non for negatives
              index--;
          }
          return index;
      }