// Gets the iterator that iterates all campaigns
// in the account.
var shoppingCampaign = AdsApp.shoppingCampaigns().withIds(["123456789"]).get();
// Loops through all campaigns in the account.
while (iterator.hasNext()) {
var campaign = iterator.next();
// Get the campaign audience's builder.
var operation = campaign.targeting().newUserListBuilder()
.withAudienceId("AUDIENCE ID GOES HERE")
.build();
// See the Builders topic for performance considerations
// when using the operation object's methods.
if (!operation.isSuccessful()) {
for (var error of operation.getErrors()) {
Logger.log(`${error}\n`);
}
}
}