def get_a_cluster(base, cluster_id, expected_status=None, wait_timeout=None):
    """Utility function that gets a Senlin cluster."""
    if expected_status is None:
        res = base.client.get_obj('clusters', cluster_id)
    else:
        base.client.wait_for_status('clusters', cluster_id, expected_status,
            wait_timeout)
        res = base.client.get_obj('clusters', cluster_id)
    return res['body']
