human
Here's a good function header given the following:
I wrote the below code

    greenlets = []
    def _inner_fake_spawn(func, *a, **kw):
        gt = greenthread.spawn(func, *a, **kw)
        greenlets.append(gt)
        return gt
    object_server.spawn = _inner_fake_spawn
    with mock.patch('swift.obj.server.spawn', _inner_fake_spawn):
        try:
            (yield)
        finally:
            for gt in greenlets:
                gt.wait()

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

@contextmanager
def fake_spawn():