def s_time_offset_from_secs(secs):
    """
    Return a string with offset from UTC in RFC3339 format, from secs.

    """

    if secs > 0:
        sign = "+"
    else:
        sign = "-"
        secs = abs(secs)

    offset_hour = secs // (60 * 60)
    offset_min = (secs // 60) % 60
    return "%s%02d:%02d" % (sign, offset_hour, offset_min)