code: def get_print_info(n_step, fill=None):
      
      if n_step > 1:
          n_digit = int(nm.log10(n_step - 1) + 1)
          if fill is None:
              format = '%%%dd' % n_digit
          else:
              format = '%%%s%dd' % (fill, n_digit)
      else:
          n_digit, format = 0, None
      return n_digit, format
docs: Returns the max. number of digits in range(n_step) and the corresponding
      format string.
  
      Examples:
  
      >>> get_print_info(11)
      (2, '%2d')
      >>> get_print_info(8)
      (1, '%1d')
      >>> get_print_info(100)
      (2, '%2d')
      >>> get_print_info(101)
      (3, '%3d')
      >>> get_print_info(101, fill='0')
      (3, '%03d')