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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 persist_experiment(experiment):
 """ Persist this experiment in the benchbuild database. Args: experiment: The experiment we want to persist. """

    from benchbuild.utils.schema import Experiment, Session

    session = Session()

    cfg_exp = experiment.id
    LOG.debug("Using experiment ID stored in config: %s", cfg_exp)
    exps = session.query(Experiment).filter(Experiment.id == cfg_exp)
    desc = str(CFG["experiment_description"])
    name = experiment.name

    if exps.count() == 0:
        newe = Experiment()
        newe.id = cfg_exp
        newe.name = name
        newe.description = desc
        session.add(newe)
        ret = newe
    else:
        exps.update({'name': name, 'description': desc})
        ret = exps.first()

    try:
        session.commit()
    except IntegrityError:
        session.rollback()
        persist_experiment(experiment)

    return (ret, session)