code: async def set_max_relative_mod(self, max_mod,
                                     timeout=OTGW_DEFAULT_TIMEOUT):
          
          if isinstance(max_mod, int) and not 0 <= max_mod <= 100:
              return None
          cmd = OTGW_CMD_MAX_MOD
          status = {}
          ret = await self._wait_for_cmd(cmd, max_mod, timeout)
          if ret not in ['-', None]:
              ret = int(ret)
          if ret == '-':
              status[DATA_SLAVE_MAX_RELATIVE_MOD] = None
          else:
              status[DATA_SLAVE_MAX_RELATIVE_MOD] = ret
          self._update_status(status)
          return ret
docs: Override the maximum relative modulation from the thermostat.
          Valid values are 0 through 100. Clear the setting by specifying
          a non-numeric value.
          Return the newly accepted value, '-' if a previous value was
          cleared, or None on failure.
  
          This method is a coroutine