def METHOD_NAME(relation_id=None, peer_relation_name='cluster',
                       peer_store_fatal=False, relation_settings=None,
                       delimiter='_', **kwargs):
    """Store passed-in arguments both in argument relation and in peer storage.
    It functions like doing relation_set() and peer_store() at the same time,
    with the same data.
    @param relation_id: the id of the relation to store the data on. Defaults
                        to the current relation.
    @param peer_store_fatal: Set to True, the function will raise an exception
                             should the peer sotrage not be avialable."""
    relation_settings = relation_settings if relation_settings else {}
    relation_set(relation_id=relation_id,
                 relation_settings=relation_settings,
                 **kwargs)
    if is_relation_made(peer_relation_name):
        for key, value in six.iteritems(dict(list(kwargs.items()) +
                                             list(relation_settings.items()))):
            key_prefix = relation_id or current_relation_id()
            peer_store(key_prefix + delimiter + key,
                       value,
                       relation_name=peer_relation_name)
    else:
        if peer_store_fatal:
            raise ValueError('Unable to detect '
                             'peer relation {}'.format(peer_relation_name))