How do I add 18 seconds to an ISO-8601 String in Python?

[Ben Finney]

Robert James Liguori <gliesian66 at gmail.com> writes:

> Thank you so much!  Btw, how do I convert back to ISO-8301?

You are consistently referring to “ISO 8301”, but I am confident that
you are not intending to talk about:

    ISO 8301: Thermal insulation -- Determination of steady-state
    thermal resistance and related properties -- Heat flow meter
    apparatus
    <URL:http://www.iso.org/iso/catalogue_detail.htm?csnumber=15421>

Please take care to refer to the correct standard code for the standard
you're referencing :-)

-- 
 \     “You say I took the name in vain / I don't even know the name / |
  `\    But if I did, well, really, what's it to you?” —Leonard Cohen, |
_o__)                                                     _Hallelujah_ |
Ben Finney