Decodes message using Caesar shift cipher

        Inverse operation of encoding, applies negative offset to Caesar shift
        cipher.

        Returns:
            String decoded with cipher.

def decoded(self):
        """Decodes message using Caesar shift cipher

        Inverse operation of encoding, applies negative offset to Caesar shift
        cipher.

        Returns:
            String decoded with cipher.
        """
        logging.info("Decoding message: {0}".format(self.message))
        self.offset = self.offset * -1
        return self.cipher()