Starts this bot in a separate thread. Therefore, this call is non-blocking.

        It will listen to all new comments created in the :attr:`~subreddits` list.

def start(self):
        """
        Starts this bot in a separate thread. Therefore, this call is non-blocking.

        It will listen to all new comments created in the :attr:`~subreddits` list.
        """
        super().start()
        comments_thread = BotThread(name='{}-comments-stream-thread'.format(self._name),
                                    target=self._listen_comments)
        comments_thread.start()
        self._threads.append(comments_thread)
        self.log.info('Starting comments stream ...')