def METHOD_NAME(
    self, description: str, channel_id: str, tags: Dict[str, str]
) -> Channel:
    arn = f"arn:aws:mediapackage:channel:{channel_id}"
    channel = Channel(
        arn=arn,
        description=description,
        channel_id=channel_id,
        tags=tags,
    )
    self._channels[channel_id] = channel
    return channel