def test_unhandledEnvironmentReadError(self):
        """
        Just like C{test_unhandledReadError}, but for the case where the
        exception that is not explicitly handled happens to be of type
        C{EnvironmentError} (C{OSError} or C{IOError}).
        """
        self.assertRaises(
            IOError,
            self._stopsReadingTest, IOError(EPERM, "Operation not permitted"))

        Just like C{test_unhandledReadError}, but for the case where the
        exception that is not explicitly handled happens to be of type
        C{EnvironmentError} (C{OSError} or C{IOError}).
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/pair/test/test_tuntap.py