def test_exception(self):
        """
        C{_trimFrames} removes traces of C{runWithWarningsSuppressed} from
        C{utils} when a synchronous exception happens in a C{TestCase}
        based test.
        """
        test = erroneous.TestAsynchronousFail('test_exception')
        frames = self.getErrorFrames(test)
        self.checkFrames(frames,
                         [('test_exception', 'twisted/trial/test/erroneous')])

        C{_trimFrames} removes traces of C{runWithWarningsSuppressed} from
        C{utils} when a synchronous exception happens in a C{TestCase}
        based test.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_reporter.py