<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def validate_broker_ids_subset(broker_ids, subset_ids):
 """Validate that user specified broker ids to restart exist in the broker ids retrieved from cluster config. :param broker_ids: all broker IDs in a cluster :type broker_ids: list of integers :param subset_ids: broker IDs specified by user :type subset_ids: list of integers :returns: bool """

    all_ids = set(broker_ids)
    valid = True
    for subset_id in subset_ids:
        valid = valid and subset_id in all_ids
        if subset_id not in all_ids:
            print("Error: user specified broker id {0} does not exist in cluster.".format(subset_id))
    return valid