[New-bugs-announce] [issue38421] email.utils.parsetime_tz does not return "None"

[David Kernan]

New submission from David Kernan <davidsmurf at gmail.com>:

email.utils.parsetime_tz() is a function which attempts to parse a date, and returns a 10-item tuple.
The first 9 items represents a time, and the last item represents the timezone offset from UTC.

In Python 2, the original behavior was to return the date, and a "None" value when there was no timezone - this is documented here:
https://docs.python.org/3/library/email.utils.html#email.utils.parsedate_tz

In Python 3 however, the code specifically prevents "None" from being returned in place of a UTC offset:
https://github.com/python/cpython/blob/3.7/Lib/email/_parseaddr.py#L53-#L54

The Python 3 documentation for email.utils.parsetime_tz() - is still the same as the 2.7 documentation, and specifically mentions that should a timezone be missing from the string, the last item will be "None"

This isn't the case:

Python 3.6.8:
>>> import email.utils
>>> date_string = 'Wed, 09 Oct 2019 08:32:37'
>>> email.utils.parsedate_tz(date_string)
(2019, 10, 9, 8, 32, 37, 0, 1, -1, 0)
----

Python 2.7.16:
>>> import email.utils
>>> date_string = 'Wed, 09 Oct 2019 08:32:37'
>>> email.utils.parsedate_tz(date_string)
(2019, 10, 9, 8, 32, 37, 0, 1, -1, None)

---

Is this an error in code, or is it a mistake in the documentation?

----------
components: email
messages: 354265
nosy: David Kernan, barry, r.david.murray
priority: normal
severity: normal
status: open
title: email.utils.parsetime_tz does not return "None"
versions: Python 3.5, Python 3.6, Python 3.7, Python 3.8, Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38421>
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