Cypher/uncypher APDUs before transmission

def transmit(self, bytes, protocol=None):
        """Cypher/uncypher APDUs before transmission"""
        cypheredbytes = self.cypher(bytes)
        data, sw1, sw2 = CardConnectionDecorator.transmit(
            self, cypheredbytes, protocol)
        if [] != data:
            data = self.uncypher(data)
        return data, sw1, sw2