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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 list_():
 # pylint: disable=redefined-builtin """ Display all MultiplyParameters nodes """

    load_dbenv_if_not_loaded(
    )  # Important to load the dbenv in the last moment

    from aiida.orm.querybuilder import QueryBuilder
    from aiida.orm import DataFactory
    MultiplyParameters = DataFactory('phtools.factors')

    qb = QueryBuilder()
    qb.append(MultiplyParameters)
    results = qb.all()

    s = ""
    for result in results:
        obj = result[0]
        s += "{}, pk: {}\n".format(str(obj), obj.pk)
    sys.stdout.write(s)