> from datetime import timedelta
> a = timedelta(days=2, hours=6)
> b = timedelta(hours=4.5)
> c = a + b
> c.days
2
> c.seconds
37800
> c.seconds / 3600
10.5
> c.total_seconds() / 3600
58.5
>

> from datetime import datetime
> a = datetime(2012, 9, 23)
> print(a + timedelta(days=10))
2012-10-03 00:00:00
>
> b = datetime(2012, 12, 21)
> d = b - a
> d.days
89
> now = datetime.today()
> print(now)
2012-12-21 14:54:43.094063
> print(now + timedelta(minutes=10))
2012-12-21 15:04:43.094063
>

> a = datetime(2012, 3, 1)
> b = datetime(2012, 2, 28)
> a - b
datetime.timedelta(2)
> (a - b).days
2
> c = datetime(2013, 3, 1)
> d = datetime(2013, 2, 28)
> (c - d).days
1
>

> a = datetime(2012, 9, 23)
> a + timedelta(months=1)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'months' is an invalid keyword argument for this function
>
> from dateutil.relativedelta import relativedelta
> a + relativedelta(months=+1)
datetime.datetime(2012, 10, 23, 0, 0)
> a + relativedelta(months=+4)
datetime.datetime(2013, 1, 23, 0, 0)
>
> # Time between two dates
> b = datetime(2012, 12, 21)
> d = b - a
> d
datetime.timedelta(89)
> d = relativedelta(b, a)
> d
relativedelta(months=+2, days=+28)
> d.months
2
> d.days
28
>