docs: def timeago(seconds=0, accuracy=4, format=0, lang="en"):
      """Translate seconds into human-readable.
  
          :param seconds: seconds (float/int).
          :param accuracy: 4 by default (units[:accuracy]), determine the length of elements.
          :param format: index of [led, literal, dict].
          :param lang: en or cn.
          :param units: day, hour, minute, second, ms.
  
      >>> timeago(93245732.0032424, 5)
      '1079 days, 05:35:32,003'
      >>> timeago(93245732.0032424, 4, 1)
      '1079 days 5 hours 35 minutes 32 seconds'
      >>> timeago(-389, 4, 1)
      '-6 minutes 29 seconds 0 ms'
      """
      assert format in [0, 1, 2], ValueError("format arg should be one of 0, 1, 2")
      negative = "-" if seconds < 0 else ""
      seconds = abs(seconds)
      if lang == "en":
          units = ("day", "hour", "minute", "second", "ms")
      elif lang == "cn":
          units = (u"天", u"小时", u"分钟", u"秒", u"毫秒")
      times = split_seconds(seconds)
      if format == 2:
          return dict(zip(units, times))
  
      day, hour, minute, second, ms = times
  
      if format == 0:
          day_str = (
              "%d %s%s, " % (day, units[0], "s" if day > 1 and lang == "en" else "")
              if day
              else ""
          )
          mid_str = ":".join(("%02d" % i for i in (hour, minute, second)))
          if accuracy > 4:
              mid_str += ",%03d" % ms
          return negative + day_str + mid_str
      elif format == 1:
          # find longest valid fields index (non-zero in front)
          valid_index = 0
          for x, i in enumerate(times):
              if i > 0:
                  valid_index = x
                  break
          else:
              valid_index = x
          result_str = [
              "%d %s%s"
              % (num, unit, "s" if lang == "en" and num > 1 and unit != "ms" else "")
              for num, unit in zip(times, units)
          ][valid_index:][:accuracy]
          result_str = " ".join(result_str)
          return negative + result_str