def test_formatUnformattableEventWithUnformattableErrorOMGWillItStop(self):
        """
        Formatting an unformattable event that has an unformattable value.
        """
        event = dict(
            log_format="{evil()}",
            evil=lambda: 1 / 0,
            recoverable="okay",
        )
        # Call formatUnformattableEvent() directly with a bogus exception.
        result = formatUnformattableEvent(event, Unformattable())
        self.assertIn("MESSAGE LOST: unformattable object logged:", result)
        self.assertIn(repr("recoverable") + " = " + repr("okay"), result)

        Formatting an unformattable event that has an unformattable value.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/logger/test/test_format.py