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Date: Mon, 26 Dec 2011 01:23:29 +1100
Subject: Re: Test None for an object that does not implement ==
From: Chris Angelico <rosuav@gmail.com>
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On Mon, Dec 26, 2011 at 1:13 AM, Roy Smith <roy@panix.com> wrote:
> If you were designing the interface from scratch, you would probably
> represent that with an exception hierarchy

Or possibly with "returns a False value", giving the option of None
for none available, False for none will ever be available. Of course,
you then have to guarantee that your live return values will always
boolify as True.

ChrisA