docs: def _display_interval(i):
      """Convert a time interval into a human-readable string.
  
      :param i: The interval to convert, in seconds.
      """
      sigils = ["d", "h", "m", "s"]
      factors = [24 * 60 * 60, 60 * 60, 60, 1]
      remain = int(i)
      result = ""
      for fac, sig in zip(factors, sigils):
          if remain < fac:
              continue
          result += "{}{}".format(remain // fac, sig)
          remain = remain % fac
      return result