code: def convert_iso_stamp(t, tz=None):
      
  
      if t is None:
          return None
  
      dt = dateutil.parser.parse(t)
      if tz is not None:
          timezone = pytz.timezone(tz)
          if dt.tzinfo is None:
              dt = timezone.localize(dt)
      return dt
docs: Convert a string in ISO8601 form into a Datetime object.  This is mainly
      used for converting timestamps sent from the TempoDB API, which are
      assumed to be correct.
  
      :param string t: the timestamp to convert
      :rtype: Datetime object