'Fill cluster OVO fields from cluster ORM instance.'

@staticmethod
def _from_db_object(context, cluster, db_cluster, expected_attrs=None):

    expected_attrs = (expected_attrs or tuple())
    for (name, field) in cluster.fields.items():
        if (((name in Cluster.OPTIONAL_FIELDS) and (name not in expected_attrs)) or (name == 'services')):
            continue
        value = getattr(db_cluster, name)
        setattr(cluster, name, value)
    cluster._context = context
    if ('services' in expected_attrs):
        cluster.services = base.obj_make_list(context, objects.ServiceList(context), objects.Service, db_cluster.services)
    cluster.obj_reset_changes()
    return cluster
