def update_attributes(self, event, channel, attr):
        """Update attribute list for current event/channel."""
        try:
            for i, sensor in enumerate(self.event_states[event]):
                if sensor[1] == int(channel):
                    self.event_states[event][i] = attr
        except KeyError:
            _LOGGING.debug('Error updating attributes for: (%s, %s)',
                           event, channel)
Update attribute list for current event/channel.