code: def format_string(current_size, total_length, elapsed_time):
      
  
      n_to_mb = current_size / _KILOBYTE / _KILOBYTE
      elapsed_str = seconds_to_time(elapsed_time)
  
      rate = _RATE_FORMAT % (n_to_mb / elapsed_time) if elapsed_time else _UNKNOWN_SIZE
      frac = float(current_size) / total_length
      bar_length = int(frac * _BAR_SIZE)
      bar = _FINISHED_BAR * bar_length + _REMAINING_BAR * (_BAR_SIZE - bar_length)
      percentage = _PERCENTAGE_FORMAT % (frac * 100)
      left_str = seconds_to_time(
          elapsed_time / current_size * (total_length - current_size)) if current_size else _UNKNOWN_SIZE
  
      humanized_total = _HUMANINZED_FORMAT % (total_length / _KILOBYTE / _KILOBYTE) + _STR_MEGABYTE
      humanized_n = _HUMANINZED_FORMAT % n_to_mb + _STR_MEGABYTE
  
      return _DISPLAY_FORMAT % (
          bar, humanized_n, humanized_total, percentage, elapsed_str, left_str, rate)
docs: Consistent format to be displayed on the screen.
      :param current_size: Number of finished object size
      :param total_length: Total object size
      :param elapsed_time: number of seconds passed since start