def list_tubes(self):
        """Return a list of tubes that this beanstalk instance knows about

        :rtype: list of tubes
        """
        with self._sock_ctx() as sock:
            self._send_message('list-tubes', sock)
            body = self._receive_data_with_prefix(b'OK', sock)
            tubes = yaml_load(body)
            return tubes
Return a list of tubes that this beanstalk instance knows about

        :rtype: list of tubes