code: public Hlr getRequestHlr(final BigInteger msisdn, final String reference) throws GeneralException, UnauthorizedException {
          if (msisdn == null) {
              throw new IllegalArgumentException("msisdn must be specified.");
          }
          if (reference == null) {
              throw new IllegalArgumentException("Reference must be specified.");
          }
          final Map<String, Object> payload = new LinkedHashMap<String, Object>();
          payload.put("msisdn", msisdn);
          payload.put("reference", reference);
          return messageBirdService.sendPayLoad(HLRPATH, payload, Hlr.class);
      }
docs: MessageBird provides an API to send Network Queries to any mobile number across the world.
  An HLR allows you to view which mobile number (MSISDN) belongs to what operator in real time and see whether the number is active.
  
  @param msisdn    The telephone number.
  @param reference A client reference
  @return Hlr Object
  @throws UnauthorizedException if client is unauthorized
  @throws GeneralException      general exception