docs: def number(items):
      """Maps numbering onto given values"""
      n = len(items)
      if n == 0:
          return items
      places = str(int(math.log10(n) // 1 + 1))
      format = '[{0[0]:' + str(int(places)) + 'd}] {0[1]}'
      return map(
          lambda x: format.format(x),
          enumerate(items)
      )