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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def update_experiment():
    '''Update the experiment status in config file'''
    experiment_config = Experiments()
    experiment_dict = experiment_config.get_all_experiments()
    if not experiment_dict:
        return None
    for key in experiment_dict.keys():
        if isinstance(experiment_dict[key], dict):
            if experiment_dict[key].get('status') != 'STOPPED':
                nni_config = Config(experiment_dict[key]['fileName'])
                rest_pid = nni_config.get_config('restServerPid')
                if not detect_process(rest_pid):
                    experiment_config.update_experiment(key, 'status', 'STOPPED')
                    continue
                rest_port = nni_config.get_config('restServerPort')
                startTime, endTime = get_experiment_time(rest_port)
                if startTime:
                    experiment_config.update_experiment(key, 'startTime', startTime)
                if endTime:
                    experiment_config.update_experiment(key, 'endTime', endTime)
                status = get_experiment_status(rest_port)
                if status:
                    experiment_config.update_experiment(key, 'status', status)