def add_xor(op_a: bytearray, op_b: bytearray) -> bytearray:
    """
    Byte-by-byte 'xor' operation for byte objects.

    Args:
        op_a: The first operand.
        op_b: The second operand.

    Returns:
        Result of the byte-by-byte 'xor' operation.
    """
    op_a = bytearray(op_a)
    op_b = bytearray(op_b)
    result_len = min(len(op_a), len(op_b))
    result = bytearray(result_len)
    for i in range(result_len):
        result[i] = op_a[i] ^ op_b[i]
    return result