code: public LookupHlr viewLookupHlr(final BigInteger phoneNumber) throws UnauthorizedException, GeneralException, NotFoundException {
          if (phoneNumber == null) {
              throw new IllegalArgumentException("phoneNumber must be specified");
          }
          final LookupHlr lookupHlr = new LookupHlr();
          lookupHlr.setPhoneNumber(phoneNumber);
          return this.viewLookupHlr(lookupHlr);
      }
docs: View a Lookup HLR (lookup)
  
  @param phoneNumber phone number for searching on hlr
  @return LookupHlr
  @throws UnauthorizedException if client is unauthorized
  @throws GeneralException      general exception
  @throws NotFoundException     phone number not found on hlr