code: public Optional<AlertChannel> show(long channelId)
      {
          Optional<AlertChannel> ret = Optional.absent();
          Collection<AlertChannel> channels = list();
          for(AlertChannel channel : channels)
          {
              if(channel.getId() == channelId)
                  ret = Optional.of(channel);
          }
          return ret;
      }
docs: Returns the alert channel with the given id.
  <P>
  This is needed because the API does not contain an operation to get a channel using the id directly.
  @param channelId The id of the alert channel to return
  @return The alert channel