I'm not clear on when I need to write datetime.what_I_want() vs datetime.datetime.what_I_want(). Is there a rule?

Hi there, Farah Hassan! It depends on how you imported datetime.

If you did this:

import datetime

... then you will need to use datetime.timedelta for example.

But if you did this:

from datetime import datetime, timedelta

... then you would only need timedelta.

The first one imports the entire datetime.py module which contains other things besides the datetime. So to access anything in it you need datetime.datetime because there are also things like datetime.date and datetime.timedelta. Hope this helps!

edited for accuracy

I originally posted an answer that was a bit incorrect. The timedelta is a part of the datetime library, not the datetime object in the datetime library. The datetime library contains an object that is also called datetime.