Call leave group API.

        https://devdocs.line.me/en/#leave

        Leave a group.

        :param str group_id: Group ID
        :param timeout: (optional) How long to wait for the server
            to send data before giving up, as a float,
            or a (connect timeout, read timeout) float tuple.
            Default is self.http_client.timeout
        :type timeout: float | tuple(float, float)

def leave_group(self, group_id, timeout=None):
        """Call leave group API.

        https://devdocs.line.me/en/#leave

        Leave a group.

        :param str group_id: Group ID
        :param timeout: (optional) How long to wait for the server
            to send data before giving up, as a float,
            or a (connect timeout, read timeout) float tuple.
            Default is self.http_client.timeout
        :type timeout: float | tuple(float, float)
        """
        self._post(
            '/v2/bot/group/{group_id}/leave'.format(group_id=group_id),
            timeout=timeout
        )