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From: Random832 <random832@fastmail.com>
To: Alexander Belopolsky <alexander.belopolsky@gmail.com>
Cc: "Python-List" <python-list@python.org>, "datetime-sig" <datetime-sig@python.org>
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Subject: Re: [Datetime-SIG] Are there any "correct" implementations of tzinfo?
Date: Mon, 14 Sep 2015 16:08:50 -0400
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On Mon, Sep 14, 2015, at 15:48, Alexander Belopolsky wrote:
> On Mon, Sep 14, 2015 at 3:44 PM, Random832 <random832@fastmail.com>
> wrote:
> 
> > It is an
> > invariant that is true today, and therefore which you can't rely on any
> > of the consumers of this 12 years old widely deployed code not to assume
> > will remain true.
> >
> 
> Sorry, this sentence does not parse.  You are missing a "not" somewhere.

Nope. I am asserting that:

This invariant is true today.
Therefore, it is likely that at least some consumers of datetime will
assume it is true.
Therefore, you cannot rely on there not being any consumers which assume
it will remain true.

It's awkward, since when I go back to analyze it it turns out that the
"not" after 'code' actually technically modifies "any" earlier in the
sentence, but the number of negatives is correct. (Though, it actually
works out even without that change, since the question of *which*
consumers rely on the invariant is unknown.)