human
I wrote the below code

    cluster = shared_cluster_internal()
    closers = []
    if conf:
        closers.extend([hadoop.conf.HDFS_CLUSTERS['default'].NN_HOST.set_for_testing('localhost'), hadoop.conf.HDFS_CLUSTERS['default'].NN_HDFS_PORT.set_for_testing(cluster.namenode_port), hadoop.conf.MR_CLUSTERS['default'].HOST.set_for_testing('localhost'), hadoop.conf.MR_CLUSTERS['default'].JT_THRIFT_PORT.set_for_testing(cluster.jt.thrift_port)])
        old_caches = clear_sys_caches()
    def finish():
        if conf:
            restore_sys_caches(old_caches)
        for x in closers:
            x()
    cluster.shutdown = finish
    return cluster

What's a good function header?

Here's a good function header?
assistant
#Here's a good function header.

def shared_cluster(conf=False):