Mine

-            for obj in objects:
-                if isinstance(obj, (components.MetaInterface, zi.Interface)):
-                    continue
-                try:
-                    if ITestCaseFactory.providedBy(obj):
-                        self._tClasses.append(obj)
-                except AttributeError:
-                    # if someone (looking in exarkun's direction)
-                    # messes around with __getattr__ in a particularly funky
-                    # way, it's possible to mess up zi's providedBy()
-                    pass