<p>Is there a way using Python's standard library to easily determine (i.e. one function call) the last day of a given month?</p>

<p>If the standard library doesn't support that, does the dateutil package support this?</p>

EDIT: See @Blair Conrad's answer for a cleaner solution
```
```
>>> import datetime
>>> datetime.date(2000, 2, 1) - datetime.timedelta(days=1)
datetime.date(2000, 1, 31)
```
```