Parsing ISO date/time strings - where did the parser go?

[Roy Smith]

In article <k2atej$4rq$1 at dont-email.me>, John Nagle <nagle at animats.com> 
wrote:

> In Python 2.7:
> 
>    I want to parse standard ISO date/time strings such as
> 
> 	2012-09-09T18:00:00-07:00
> 
> into Python "datetime" objects.  The "datetime" object offers
> an output method , datetimeobj.isoformat(), but not an input
> parser.  There ought to be
> 
> 	classmethod datetime.fromisoformat(s)
> 
> but there isn't.  I'd like to avoid adding a dependency on
> a third party module like "dateutil".

I'm curious why?  I really think dateutil is the way to go.

It's really amazing (and unfortunate) that datetime has isoformat(), but 
no way to go in the other direction.