Python 2.6, 3 abstract base class misunderstanding
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Published on 2010-05-19T00:46:08Z
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2010/05/19
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I'm not seeing what I expect when I use ABCMeta and abstractmethod.
This works fine in python3:
from abc import ABCMeta, abstractmethod
class Super(metaclass=ABCMeta):
@abstractmethod
def method(self):
pass
a = Super()
TypeError: Can't instantiate abstract class Super ...
And in 2.6:
class Super():
__metaclass__ = ABCMeta
@abstractmethod
def method(self):
pass
a = Super()
TypeError: Can't instantiate abstract class Super ...
They both also work fine (I get the expected exception) if I derive Super from object, in addition to ABCMeta.
They both "fail" (no exception raised) if I derive Super from list.
I want an abstract base class to be a list but abstract, and concrete in sub classes.
Am I doing it wrong, or should I not want this in python?
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