are classes in the new-style model--built-in types are now classesand their instances derive from objecttootype('spam')type(str(isinstance('spam'objecttrue isinstance(strobjecttrue same for built-in types (classesin facttype itself derives from objectand object derives from typeeven though the two are different objects-- circular relationship that caps the object model and stems from the fact that types are classes that generate classestype(typetype(objectall classes are typesand vice versa isinstance(typeobjecttrue isinstance(objecttypetrue type is object false all classes derive from objecteven type types make classesand type is class implications for defaults the preceding may seem obscurebut this model has number of practical implications for one thingit means that we sometimes must be aware of the method defaults that come with the explicit or implicit object root class in new-style classes onlyc:\codepy - dir(object['__class__''__delattr__''__doc__''__format__''__getattribute__''__hash__'__init__''__new__''__reduce__''__reduce_ex__''__repr__''__setattr__'__sizeof__''__str__''__subclasshook__'class cpass __bases__ classic classes do not inherit from object ( ( __repr__ attributeerrorc instance has no attribute '__repr__class (object)pass new-style classes inherit object defaults __bases__ (, ( __repr__ :\codepy - advanced class topics