Cloud application studio - edit or test a root field on an existing object

Hello,

I extend the Customer object and I add a script (beforesave) on Common space.

I can add an element and play with it but, to manage an old existing field it's difficult.

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import ABSL;

import AP.Common.GDT;

import AP.FO.BusinessPartner.Global;

var hello = 1;

if ( this.ToRoot.ABCClassifications.CustomerABCClassificationCode.content == "B" ) {

hello = hello + 1;

}

this.addedField = hello;

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This test doesn't work. How can I access to a root element ?