code: def encipher(self,string):
                     
          string = self.remove_punctuation(string)#,filter='[^'+self.key+']')
          ret = ''
          for c in range(0,len(string)):
              ret += self.encipher_char(string[c])
          return ret
docs: Encipher string using Polybius square cipher according to initialised key.
  
          Example::
  
              ciphertext = Polybius('APCZWRLFBDKOTYUQGENHXMIVS',5,'MKSBU').encipher(plaintext)     
  
          :param string: The string to encipher.
          :returns: The enciphered string. The ciphertext will be twice the length of the plaintext.