def aes_key(self, data):
        """
        AES128 key to program into YubiKey.

        Supply data as either a raw string, or a hexlified string prefixed by 'h:'.
        The result, after any hex decoding, must be 16 bytes.
        """
        old = self.key
        if data:
            new = self._decode_input_string(data)
            if len(new) == 16:
                self.key = new
            else:
                raise yubico_exception.InputError('AES128 key must be exactly 16 bytes')

        return old
def aes_key ( self , data ) : old = self . key if data : new = self . _decode_input_string ( data ) if len ( new ) == 16 : self . key = new else : raise yubico_exception . InputError ( 'AES128 key must be exactly 16 bytes' ) return old
AES128 key to program into YubiKey.

        Supply data as either a raw string, or a hexlified string prefixed by 'h:'.
        The result, after any hex decoding, must be 16 bytes.