human
Complete the below
def benchmark(scenario, operation, metric, num_samples):

    ''''Perform benchmarking of the operation within a scenario.
    :param IScenario scenario: A load scenario.
    :param IOperation operation: An operation to perform.
    :param IMetric metric: A quantity to measure.
    :param int num_samples: Number of samples to take.
    :return: Deferred firing with a tuple containing one list of
    benchmark samples and one scenario metrics result. See the
    ``sample`` function for the structure of the samples.  The
    scenario metrics are a dictionary containing information about
    the scenario.'
    '''
assistant
#Here is the Python program you requested.
    scenario_established = scenario.start()
    samples = []
    def collect_samples(ignored):
        collecting = Deferred()
        task = cooperate((sample(operation, metric, i).addCallback(samples.append) for i in range(num_samples)))
        def stop_sampling_on_scenario_collapse(failure):
            task.stop()
            collecting.errback(failure)
        scenario.maintained().addErrback(stop_sampling_on_scenario_collapse)
        task.whenDone().addCallbacks((lambda ignored: collecting.callback(samples)), (lambda ignored: None))
        return collecting
    benchmarking = scenario_established.addCallback(collect_samples)
    def stop_scenario(samples):
        d = scenario.stop()
        def combine_results(scenario_metrics):
            return (samples, scenario_metrics)
        d.addCallback(combine_results)
        return d
    benchmarking.addCallbacks(stop_scenario, bypass, errbackArgs=[scenario.stop])
    return benchmarking