Haneef, thank you for the explanation.  Any such addition would need a PEP.  But I agree with Marc-Andre that supporting the multitude of calendars is out of scope for the stdlib.  So I suspect such a PEP would be rejected, with the suggestion already given here, that this belongs on PyPI.  An existing example is the time module of the astropy module,
http://docs.astropy.org/en/stable/time/index.html .

I could be wrong, but I have a vague impression that expanding calendar support has been requested and rejected before.  We have enough to do properly supporting the existing time, datetime, and calendar modules.