def test_get_only_proxy(self):
        class Something(object):
            foo = 'foo'
        class SomethingElse:
            foo = 'foo'

        for thing in Something, SomethingElse, Something(), SomethingElse:
            proxy = _get_proxy(thing)

            @patch.object(proxy, 'foo', 'bar')
            def test():
                self.assertEqual(proxy.foo, 'bar')
            test()
            self.assertEqual(proxy.foo, 'foo')
            self.assertEqual(thing.foo, 'foo')
            self.assertNotIn('foo', proxy.__dict__)