code: def encipher(self,string,keep_punct=False):
                 
          if not keep_punct: string = self.remove_punctuation(string)
          ret = ''
          for c in string.upper():
              if c.isalpha(): ret += self.key[self.a2i(c)]
              else: ret += c
          return ret
docs: Encipher string using Atbash cipher.
  
          Example::
  
              ciphertext = Atbash().encipher(plaintext)     
  
          :param string: The string to encipher.
          :param keep_punct: if true, punctuation and spacing are retained. If false, it is all removed. Default is False. 
          :returns: The enciphered string.