metaclass

ast nomail at invalid.com
Fri Feb 5 02:12:09 EST 2016


Hi

I am looking the relationship between some classes
from the enum module

>>> from enum import EnumMeta, Enum

>>> class Color(Enum):
              pass

>>> type(EnumMeta)
<class 'type'>
>>> EnumMeta.__bases__
(<class 'type'>,)
>>> 

so EnumMeta is a metaclass, it is an instance of type
and inherit from type too.

>>> type(Enum)
<class 'enum.EnumMeta'>
>>> Enum.__bases__
(<class 'object'>,)

so Enum is an instance of EnumMeta
and Enum inherit from object

>>> type(Color)
<class 'enum.EnumMeta'>
>>> Color.__bases__
(<enum 'Enum'>,)

so Color is an instance of EnumMeta and
inherit from Enum

It is not obvious to me that Color is an instance
of EnumMeta. Is it a python rule that if a class C
inherit from a class which is an instance of
a metaclass, then class C is an instance of the
same metaclass too ?

Or was it feasible to guess that ?






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