docs: def progress_str(max_val, lbl='Progress: ', repl=False, approx=False,
                   backspace=PROGGRESS_BACKSPACE):
      r""" makes format string that prints progress: %Xd/MAX_VAL with backspaces
  
      NOTE: \r can be used instead of backspaces. This function is not very
      relevant because of that.
  
      """
      # string that displays max value
      max_str = six.text_type(max_val)
      if approx:
          # denote approximate maximum
          max_str = '~' + max_str
      dnumstr = six.text_type(len(max_str))
      # string that displays current progress
      cur_str = '%' + dnumstr + 'd'
      # If user passed in the label
      if repl:
          _fmt_str = lbl.replace('<cur_str>', cur_str).replace('<max_str>', max_str)
      else:
          _fmt_str = lbl + cur_str + '/' + max_str
      if backspace:
          # put backspace characters into the progress string
          # (looks nice on normal terminals)
          #nBackspaces = len(_fmt_str) - len(dnumstr) + len(max_str)
          #backspaces = '\b' * nBackspaces
          #fmt_str = backspaces + _fmt_str
          # FIXME: USE CARAGE RETURN INSTEAD OF BACKSPACES
          fmt_str = '\r' + _fmt_str
      else:
          # FIXME: USE CARAGE RETURN INSTEAD OF BACKSPACES
          # this looks better on terminals without backspaces
          fmt_str = _fmt_str + '\n'
      return fmt_str