def test_ambiguousFailureFromGenerator(self):
        """
        When a generator reraises a different exception,
        L{Failure._findFailure} above the generator should find the reraised
        exception rather than original one.
        """
        def generator():
            try:
                yield
            except:
                [][1]
        g = generator()
        next(g)
        f = getDivisionFailure()
        try:
            self._throwIntoGenerator(f, g)
        except:
            self.assertIsInstance(failure.Failure().value, IndexError)

        When a generator reraises a different exception,
        L{Failure._findFailure} above the generator should find the reraised
        exception rather than original one.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_failure.py