Re: Coming In Python 3.15: Sentinel Values

Lawrence D’Oliveiro <[email protected]> Mon, 11 May 2026 06:24:32 -0000 (UTC)
Newsgroups comp.lang.python
Organization A noiseless patient Spider
Message-ID <[email protected]>
On Sun, 10 May 2026 21:01:00 -0700, Paul Rubin wrote:

> Lawrence D’Oliveiro <[email protected]> writes:
>>
>> For those times when a simple “None” marker element is not
>> sufficient, this will be very convenient.
>
> object() has always worked for me.

I have done the same, on a few occasions. That’s been a common idiom
among Python programmers since practically forever. The PEP discusses
why this is less than an optimal solution: less-than-explanatory
diagnostics, and difficulty with type signatures for static typing.
Also, an “is” comparison fails if you should (inadvertently or
otherwise) make a copy of your sentinel object.