zoneinfo and tzdata

[Mike Dewhirst]

The zoneinfo module does not work on Windows unless you have installed 
tzdata.

On Ubuntu that data seems to exist already. Not sure how or why but it 
obviously isn't there in a Windows virtualenv unless deliberately installed.

I just spent a bit of time trying to switch from pytz to zoneinfo in 
Django without luck. I then asked and greatly embarrassed ChatGPT which 
kept apologizing when I fed back all the zoneinfo errors its advice caused.

It wasn't until I read the docs that I saw zoneinfo would get timezone 
data from tzdata if the real info wasn't where it first looked.

As soon as I installed tzdata, ChatGPT's advice started to work. When I 
reported this, it was very grateful and assured me my generosity in 
bothering to correct it would be very beneficial for other users having 
similar problems.

Might I suggest that if zoneinfo comes up empty-handed it should raise 
an error saying no timezone information was found?

Currently, it just nominates the timezone key you attempt to use. Behind 
the scenes it surely knows there are no such keys. In that case it might 
suggest installing tzdata.

Cheers

Mike