code: def _set_all_zone_stereo(self, zst_on):
          
          command_url = self._urls.command_set_all_zone_stereo
          if zst_on:
              command_url += "ZST ON"
          else:
              command_url += "ZST OFF"
  
          try:
              return self.send_get_command(command_url)
          except requests.exceptions.RequestException:
              _LOGGER.error(
                  "Connection error: unable to set All Zone Stereo to %s",
                  zst_on)
              return False
docs: Set All Zone Stereo option on the device.
  
          Calls command to activate/deactivate the mode
          Return "True" when successfully sent.