python - TypeError: can't compare offset-naive and offset-aware datetimes -

the server hosts db in u.s. when add item db, want time stored using australia/sydney time. regardless of country user in, if retrieve record, should returned using australia/sydney time. doing this:

tz = pytz.timezone('australia/sydney') orderdate = datetime.now(tz) return add_order_to_db(orderid, orderdate, ordercost) # adds order object db 

the issue arises when want update orderdate above order object.

tz = pytz.timezone('australia/sydney') orderdate = datetime.now(tz)  contextlib.closing(dbsession()) session:     try:         existingorder = session.query(order).filter_by(ordersid=orderid).first()         existingorder.ordersdate = orderdate         session.commit()     except exc.sqlalchemyerror, error:         session.rollback()         raise_database_error(error) 

order object

class order(base): __tablename__ = 'orders'  ordersid = column(integer, primary_key=true) ordersdate = column(datetime, nullable=false) orderscost = column(numeric(19, 4), nullable=false) 

in mysql, ordersdate datetime variable.

how retaining offset-naive nature of datetime object applying offset current utc time?

 tz = pytz.timezone('australia/sydney')  orderdate = datetime.datetime.now() +  tz._utcoffset