The `dateutil` module provides powerful extensions to the standard `datetime` module, available in Python. 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, UTC timezone, and Windows registry-based time zones. * Internal up-to-date world timezone information based on Olson's database. * Computing of Easter Sunday dates for any given year, using Western, Orthodox or Julian algorithms; * More than 400 test cases.