'Join the player to a group.'

@soco_error
def join(self, master):

    coord = [device for device in self.hass.data[DATA_SONOS] if (device.entity_id == master)]
    if (coord and (master != self.entity_id)):
        coord = coord[0]
        if (coord.soco.group.coordinator != coord.soco):
            coord.soco.unjoin()
        self._player.join(coord.soco)
        self._coordinator = coord
    else:
        _LOGGER.error('Master    not    found    %s', master)
