code: def mktime_tz(data):
      
      if data[9] is None:
          # No zone info, so localtime is better assumption than GMT
          return time.mktime(data[:8] + (-1,))
      else:
          t = calendar.timegm(data)
          return t - data[9]
docs: Turn a 10-tuple as returned by parsedate_tz() into a POSIX timestamp.