I understand why you added this test in this method, but it feels odd. It's surprising to me, reading just the method name, that it changes its behavior if we're in legacy mode or not. It might be better to either change its name, or to move this test to line 59 (i.e. ``if not self.legacy_mode and self._same_read_and_write_url()``

This will make it harder to test, without also refactoring the configure() method...