human
I wrote the below code

    global val, called
    val = None
    called = False
    class X(object, ):
        def __new__(cls):
            global val
            if (val == None):
                val = object.__new__(cls)
            return val
        def __del__(self):
            called = True
    a = X()
    b = X()
    AreEqual(id(a), id(b))
    import gc
    gc.collect()
    AreEqual(called, False)

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

def test_finalizer():