A bug in function applyZoneOffset which is in SOAPpy/Parser.py
When run convertDateTime("2010-03-31T23:47:59-04:00", "dateTime"), the returned date is (2010, 02, 60, 3, 47, 59).
It should be (2010, 04, 1, 3, 47, 59). BTW, My local timezone is EDT
Please look at applyZoneOffset function, it only deals with going back. Line 602 in newest 0.12 version.