code: @Override
      public SubsequentDirectoryNumberMessage createSDN() {
          SubsequentDirectoryNumberMessage msg = new SubsequentDirectoryNumberMessageImpl(_SDN_HOLDER.mandatoryCodes,
                  _SDN_HOLDER.mandatoryVariableCodes, _SDN_HOLDER.optionalCodes, _SDN_HOLDER.mandatoryCodeToIndex,
                  _SDN_HOLDER.mandatoryVariableCodeToIndex, _SDN_HOLDER.optionalCodeToIndex);
          return msg;
      }
docs: /*
  (non-Javadoc)
  
  @see org.restcomm.protocols.ss7.isup.ISUPMessageFactory#createSDN()