Can't subtract offset-naive and offset-aware datetimes

Question

I have a timezone aware timestamptz field in PostgreSQL. When I pull data from the table, I then want to subtract the time right now so I can get it's age.

The problem I'm having is that both datetime.datetime.now() and datetime.datetime.utcnow() seem to return timezone unaware timestamps, which results in me getting this error:

TypeError: can't subtract offset-naive and offset-aware datetimes 

Is there a way to avoid this (preferably without a third-party module being used).

EDIT: Thanks for the suggestions, however trying to adjust the timezone seems to give me errors.. so I'm just going to use timezone unaware timestamps in PG and always insert using:

NOW() AT TIME ZONE 'UTC'

That way all my timestamps are UTC by default (even though it's more annoying to do this).

Answer 1

have you tried to remove the timezone awareness?

from http://pytz.sourceforge.net/

naive = dt.replace(tzinfo=None)

may have to add time zone conversion as well.

edit: Please be aware the age of this answer. An answer involving ADDing the timezone info instead of removing it in python 3 is below. https://stackoverflow.com/a/25662061/93380