[Zope] how to use datetime?

hi, i've been sweating with datetime objects the whole day, but still cant figure out some simple things: - documentation ? only in the zope api reference? - how do i make a datetime object which is now+2 hours? i'm sure there is a simple way, ... like DateTime()+2 which would be great if i could add hours, minutes or seconds so easy ... thanks for the help jonatan