type、object、class之间的关系

class Foo:
    pass

print(type(int))            # <class ‘type‘>
print(type(str))            # <class ‘type‘>
print(type(Foo))            # <class ‘type‘>
print(type(object))         # <class ‘type‘>
print(type(type))           # <class ‘type‘>

print(int.__bases__)        # (<class ‘object‘>,)
print(str.__bases__)        # (<class ‘object‘>,)
print(Foo.__bases__)        # (<class ‘object‘>,)
print(object.__bases__)     # ()
print(type.__bases__)       # (<class ‘object‘>,)