def test_notLookupMissingByName(self):
        """
        Names not defined with a L{ValueConstant} instance cannot be looked up
        using L{Values.lookupByName}.
        """
        self.assertRaises(ValueError, self.STATUS.lookupByName, "lookupByName")
        self.assertRaises(ValueError, self.STATUS.lookupByName, "__init__")
        self.assertRaises(ValueError, self.STATUS.lookupByName, "foo")

        Names not defined with a L{ValueConstant} instance cannot be looked up
        using L{Values.lookupByName}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_constants.py