Rollback the configuration.

        This method rolls back the configuration on the device.

        Args:
            label (text): The configuration label ID
            plane: (text): sdr or admin

        Returns:
            A string with commit label or None

def rollback(self, label=None, plane='sdr'):
        """Rollback the configuration.

        This method rolls back the configuration on the device.

        Args:
            label (text): The configuration label ID
            plane: (text): sdr or admin

        Returns:
            A string with commit label or None

        """
        begin = time.time()
        rb_label = self._chain.target_device.rollback(label=label, plane=plane)
        elapsed = time.time() - begin
        if label:
            self.emit_message("Configuration rollback last {:.0f}s. Label: {}".format(elapsed, rb_label),
                              log_level=logging.INFO)
        else:
            self.emit_message("Configuration failed.", log_level=logging.WARNING)

        return rb_label