code: public boolean addTimer(VacuumTimer timer) throws CommandExecutionException {
          if (timer == null) throw new CommandExecutionException(CommandExecutionException.Error.INVALID_PARAMETERS);
          JSONArray tm = timer.construct();
          if (tm == null) return false;
          JSONArray payload = new JSONArray();
          payload.put(tm);
          return sendOk("set_timer", payload);
      }
docs: Add a new scheduled cleanup.
  @param timer The new timer to set.
  @return True if the command was received successfully.
  @throws CommandExecutionException When there has been a error during the communication or the response was invalid.