There is a unused variable in Lib/test/test_frame.py.

    def test_clear_executing_generator(self):
        # Attempting to clear an executing generator frame is forbidden.
        endly = False
        def g():
            nonlocal endly
            try:
                1/0
            except ZeroDivisionError as e:
                f = e.__traceback__.tb_frame
                with self.assertRaises(RuntimeError):
                    f.clear()
                with self.assertRaises(RuntimeError):
                    f.f_back.clear()
                yield f
            finally:
                endly = True
        gen = g()
        f = next(gen)
        self.assertFalse(endly)

The variable f is hanging without any purpose.

Attached the patch to give purpose to variable f.

New changeset 34e1ecb8edd2 by Antoine Pitrou in branch 'default':
Issue #18666: improve test_frame a bit. Patch by Vajrasky Kok.
http://hg.python.org/cpython/rev/34e1ecb8edd2

Good idea, thank you!