def get_flows_from_logbook(logbook, persistence_backend):
    """
    Gets all flows for a logbook
    :param obj logbook: A TaskFlow logbook
    :param obj persistence_backend: A connection to the persistence backend
    :return iter[obj, ..] all_flows: An iterable of flow objects
    """
    return persistence_backend.get_flows_for_book(logbook.uuid)