def decipher(self,message):
return self.encipher(message)<EOL>
Decipher string using M209 cipher according to initialised key. Punctuation and whitespace
        are removed from the input. The encipher and decipher operations of the M209 are identical.

        Example (continuing from the example above)::

            plaintext = m.decipher(ciphertext)     

        :param string: The string to decipher.
        :returns: The deciphered string.