Can't subtract offset-naive and offset-aware datetimes
have you tried to remove the timezone awareness?
from 
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. 
The correct solution is to add the timezone info e.g., to get the current time as an aware datetime object in Python 3:
from datetime import datetime, timezonenow = datetime.now(timezone.utc)
On older Python versions, you could define the
utc tzinfo object yourself (example from datetime docs):
from datetime import tzinfo, timedelta, datetimeZERO = timedelta(0)class UTC(tzinfo): def utcoffset(self, dt): return ZERO def tzname(self, dt): return "UTC" def dst(self, dt): return ZEROutc = UTC()
then:
now = datetime.now(utc)
I know some people use Django specifically as an interface to abstract this type of database interaction. Django provides utilities that can be used for this:
from django.utils import timezonenow_aware = timezone.now()
You do need to set up a basic Django settings infrastructure, even if you are just using this type of interface (in settings, you need to include
USE_TZ=True to get an aware datetime).
By itself, this is probably nowhere near enough to motivate you to use Django as an interface, but there are many other perks. On the other hand, if you stumbled here because you were mangling your Django app (as I did), then perhaps this helps...