def METHOD_NAME(self, old_flow, new_flow):
    if old_flow is not None and old_flow.flow is not new_flow.flow:
        raise MeasurementError("Aggregating incompatible Flows")
    new_result = AggregatedXDPBenchMeasurementResults(
        measurement=self, flow=new_flow.flow
    )
    new_result.add_results(old_flow)
    new_result.add_results(new_flow)
    return new_result