This new patch also adds a function named gc.is_tracked() which returns
True if the object is tracked by the GC:

>>> import gc
>>> gc.is_tracked(1)
False
>>> gc.is_tracked([])
True
>>> gc.is_tracked(())
True
>>> gc.is_tracked((0,1))
False
>>> gc.is_tracked((0,"a"))
False
>>> gc.is_tracked((0,[]))
True
>>> gc.is_tracked((0,(1,2)))
False
>>> gc.is_tracked((0,(1,0.55)))
False
>>> gc.is_tracked((0,(1,{})))
True
>>> gc.is_tracked((None, True, False, "a", (1,2,u"z",("another",
"nested", u"tuple")), int))
False
>>> gc.is_tracked(gc)
True


(as you see the empty tuple is considered tracked, this is not important
since it is a singleton anyway)