code: def decipher(self,string):
                          
          step2 = ColTrans(self.keyword).decipher(string)
          step1 = PolybiusSquare(self.key,size=6,chars='ADFGVX').decipher(step2)
          return step1
docs: Decipher string using ADFGVX cipher according to initialised key information. Punctuation and whitespace
          are removed from the input.       
  
          Example::
  
              plaintext = ADFGVX('ph0qg64mea1yl2nofdxkr3cvs5zw7bj9uti8','HELLO').decipher(ciphertext)     
  
          :param string: The string to decipher.
          :returns: The enciphered string.