how to get deviceUniqueIdentifier ?

I am trying to understand to get the deviceUniqueIdentifier info.

I imagined as it is below.
but I think it is not going to work. How can i assign the id value to a variable?

var idNumber : String;
function Start()
{

idNumber = SystemInfo.deviceUniqueIdentifier;

}

it is :

idNumber =SystemInfo.deviceUniqueIdentifier;

:smile: