def typing(self, *, channel: str):
        """Sends a typing indicator to the specified channel.

        This indicates that this app is currently
        writing a message to send to a channel.

        Args:
            channel (str): The channel id. e.g. 'C024BE91L'

        Raises:
            SlackClientNotConnectedError: Websocket connection is closed.
        """
        payload = {"id": self._next_msg_id(), "type": "typing", "channel": channel}
        self.send_over_websocket(payload=payload)