async def _add_participant(self, channel, participant_str):
    topic = channel.topic
    new_topic = None
    if (topic == ''):
        new_topic = participant_str
    else:
        new_topic = ((topic + self._PARTICIPANT_DELIMITER) + participant_str)
    (await self._client.edit_channel(channel, topic=new_topic))
    return
async def _add_participant(self, channel, participant_str):
    topic = channel.topic
    new_topic = None
    if (topic == ):
        new_topic = participant_str
    else:
        new_topic = ((topic + self._PARTICIPANT_DELIMITER) + participant_str)
    (await self._client.edit_channel(channel, topic=new_topic))
    return