RFC 3339 defines a standard for Date and Time on the Internet. 
http://www.ietf.org/rfc/rfc3339.txt Given that Python is increasingly 
popular on the Internet is should include convenience function to 
generate RFC 3339 timestamps in standard library.

It is impossible to generate RFC 3339 timestamps (that are also valid 
ISO 8601 timestamps) with datetime.strftime() alone, so the following 
code should be used:

import datetime

def rfcformat(dt):
    """ Output datetime in RFC 3339 format that is also valid ISO 8601
        timestamp representation"""

    if dt.tzinfo is None:
        suffix = "-00:00"
    else:
        suffix = dt.strftime("%z")
        suffix = suffix[:-2] + ":" + suffix[-2:]
    return dt.strftime("%Y-%m-%dT%H:%M:%S") + suffix