docs: def format_sec(s):
      """
      Format seconds in a more human readable way. It supports units down to
      nanoseconds.
  
      :param s: Float of seconds to format
      :return: String second representation, like 12.4 us
      """
  
      prefixes = ["", "m", "u", "n"]
      unit = 0
  
      while s < 1 and unit + 1 < len(prefixes):
          s *= 1000
          unit += 1
  
      return "{:.1f} {}s".format(s, prefixes[unit])