Returns true if the channel is in a settled state, false otherwise.

def channel_is_settled(
            self,
            participant1: Address,
            participant2: Address,
            block_identifier: BlockSpecification,
            channel_identifier: ChannelID,
    ) -> bool:
        """ Returns true if the channel is in a settled state, false otherwise. """
        try:
            channel_state = self._get_channel_state(
                participant1=participant1,
                participant2=participant2,
                block_identifier=block_identifier,
                channel_identifier=channel_identifier,
            )
        except RaidenRecoverableError:
            return False
        return channel_state >= ChannelState.SETTLED