code: def int2str(self, num):
          
          if int(num) != num:
              raise TypeError('number must be an integer')
          if num < 0:
              raise ValueError('number must be positive')
          radix, alphabet = self.radix, self.alphabet
          if radix in (8, 10, 16) and \
                  alphabet[:radix].lower() == BASE85[:radix].lower():
              return ({8: '%o', 10: '%d', 16: '%x'}[radix] % num).upper()
          ret = ''
          while True:
              ret = alphabet[num % radix] + ret
              if num < radix:
                  break
              num //= radix
          return ret
docs: Converts an integer into a string.
  
          :param num: A numeric value to be converted to another base as a
                      string.
  
          :rtype: string
  
          :raise TypeError: when *num* isn't an integer
          :raise ValueError: when *num* isn't positive