Should have included the units in the name or required a choice of unit to be selected as part of the value. Sorry, just a bugbear of mine.
oh, you can use commas too.
and if you're still not thinking this is fun, here's a quote from Wikipedia "But keep in mind that "PT36H" is not the same as "P1DT12H" when switching from or to Daylight saving time."
just add a unit to your period parameters. sigh.
It's pretty simple actually.
> 'X weeks' or 'Y hours Z minutes'
PxW, PTyHzM. So simple that I learned it in a few seconds.
/s