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Article:		A Primer on Python Metaclass Programming
Subject:		type not the same as new.classobj
Date:		2007-07-13 16:17:19
From:		hattawayd

In the text you mention: "The class type works as a class factory in the same way that the function new.classobj does" I'm not sure what the whole different is, but there is a difference. One example that bit me with Python2.5: >>> test = new.classobj('test', (), {'a1': 'tA1'}) >>> test.__dict__ {'a1': 'tA1', '__module__': '__main__', '__doc__': None} >>> test = type('test', (), ('test', (), {'a1': 'tA1'}) >>> test.__dict__ <dictproxy object at 0x00963A70> So if your code, or the libraries you're using (in my case Django) depend on the value __dict__ then make sure to use the right one.

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type not the same as new.classobj
2007-07-13 17:09:41 David_Mertz [View]

Python 2.5 made this change, so I obviously didn't know about it when I wrote the article. If you want to assure that you are looking at a real dict, you should be able to wrap the dictproxy object in an idempotent dict() initializer (i.e. no harm in wrapping a real dict that way either)