My understanding of the python documentation and the ISO 8601 standard is that the digits in a timestamp representing hours, minutes and seconds shall always be in pairs of 2 digits (hh, mm, ss), i.e. when a number is less than 10 it should be preceded by 0. 
In the example I give, the minute figure is split between minutes and seconds by the  python library function which I consider a bug: 
datetime.datetime.strptime('20110817T1234','%Y%m%dT%H%M%S') 
gives
datetime.datetime(2011, 8, 17, 12, 3, 4)