Advertising with 128-bit and 16-bit UUID?

Thanks @Gordon! Yet another question somewhat related. It seems I can't use a const in NRF.setServices(). Is there a reason; I'd really rather not have to use a literal each time for the UUID strings?

This works:

NRF.setServices({
  "00001523-1212-EFDE-1523-785FEABCD123" : {
    "00001524-1212-EFDE-1523-785FEABCD123" : { // button
      value : 0x00, // optional
...

This doesn't (and doesn't throw an error to the IDE when loaded):

const  LBS_UUID  = "00001523-1212-EFDE-1523-785FEABCD123";
const  LBS_BUTTON = "00001524-1212-EFDE-1523-785FEABCD123";
const  LBS_LED = "00001525-1212-EFDE-1523-785FEABCD123";

NRF.setServices({
  LBS_UUID : {
    "00001524-1212-EFDE-1523-785FEABCD123" : { // button
      value : 0x00, // optional
  ...