human
I wrote the below code

    def decorator(test_method):
        '\n                                :param    test_method:    The    test    method    that    will    be    called    when    the\n                                                cluster    is    available    and    which    will    be    supplied    with    the\n                                                ``cluster``keyword    argument.\n                                '
        def call_test_method_with_cluster(cluster, test_case, args, kwargs):
            kwargs['cluster'] = cluster
            if required_backend:
                backend_type = get_dataset_backend(test_case)
                if (backend_type != required_backend):
                    raise SkipTest('This    test    requires    backend    type    {}    but    is    being    run    on    {}.'.format(required_backend.name, backend_type.name))
                kwargs['backend'] = get_backend_api(cluster.cluster_uuid)
            return test_method(test_case, *args, **kwargs)
        @wraps(test_method)
        def wrapper(test_case, *args, **kwargs):
            waiting_for_cluster = _get_test_cluster(reactor)
            def clean(cluster):
                existing = len(cluster.nodes)
                if (num_nodes > existing):
                    raise SkipTest('This    test    requires    a    minimum    of    {necessary}    nodes,    {existing}    node(s)    are    set.'.format(necessary=num_nodes, existing=existing))
                return cluster.clean_nodes().addCallback((lambda _: cluster.transform(['nodes'], (lambda nodes: nodes[:num_nodes]))))
            waiting_for_cluster.addCallback(clean)
            def enable_container_agent(cluster):
                def configure_container_agent(node):
                    return ensure_container_agent_enabled(node, require_container_agent)
                d = defer.gatherResults(map(configure_container_agent, cluster.nodes), consumeErrors=True)
                d.addCallback((lambda _: cluster))
                return d
           ...

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

def require_cluster(num_nodes, required_backend=None, require_container_agent=False):