def testReturnNoValue(self):
        """Ensure a standard python return results in a None result."""
        def _noReturn():
            yield 5
            return
        _noReturn = inlineCallbacks(_noReturn)

        return _noReturn().addCallback(self.assertEqual, None)
Ensure a standard python return results in a None result.
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_defgen.py