by recht@ and updated by me.
The dateutil module provides powerful extensions to the standard datetime
module, available in Python 2.3+.
Features
* Computing of relative deltas (next month, next year, next monday, last week
of month, etc);
* Computing of relative deltas between two given date and/or datetime objects;
* Computing of dates based on very flexible recurrence rules, using a superset
of the iCalendar specification. Parsing of RFC strings is supported as well.
* Generic parsing of dates in almost any string format;
* Timezone (tzinfo) implementations for tzfile(5) format files
(/etc/localtime, /usr/share/zoneinfo, etc), TZ environment string (in all
known formats), iCalendar format files, given ranges (with help from
relative deltas), local machine timezone, fixed offset timezone, and UTC
timezone.
* Computing of Easter Sunday dates for any given year, using Western, Orthodox
or Julian algorithms;
* More than 400 test cases.
