Update test

Author: markshannon

Lib/test/test_asyncio/test_taskgroups.py

@@ -997,7 +997,7 @@ async def coro_fn():
 
         self.assertIsNone(task_wr())
         self.assertIsInstance(exc, _Done)
-        self.assertListEqual(gc.get_referrers(exc), no_other_refs())
+        self.assertListEqual(gc.get_referrers(exc), [])
 
     async def test_exception_refcycles_propagate_cancellation_error(self):
         """Test that TaskGroup deletes propagate_cancellation_error"""