def test_newStyleClassesOnly(self):
        """
        Test that C{self.module} has no old-style classes in it.
        """
        try:
            module = namedAny(self.module)
        except ImportError as e:
            raise unittest.SkipTest("Not importable: {}".format(e))

        oldStyleClasses = []

        for name, val in inspect.getmembers(module):
            if hasattr(val, "__module__") \
               and val.__module__ == self.module:
                if isinstance(val, types.ClassType):
                    oldStyleClasses.append(fullyQualifiedName(val))

        if oldStyleClasses:

            self.todo = "Not all classes are made new-style yet. See #8243."

            for x in forbiddenModules:
                if self.module.startswith(x):
                    delattr(self, "todo")

            raise unittest.FailTest(
                "Old-style classes in {module}: {val}".format(
                    module=self.module,
                    val=", ".join(oldStyleClasses)))

        Test that C{self.module} has no old-style classes in it.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_nooldstyle.py