AdGroupLabelOperation in PHP, How To?

[John VV]

I am using the PHP Library to add a label to an adGroup but having some problems with the operation:

$ad_group_id = '123456';
$labels = array('78910');
operations = array();
foreach($labels as $label_id){
      $adGroupLabel = new AdGroupLabel();
      $adGroupLabel->setAdGroupId($ad_group_id);
      $adGroupLabel->setLabelId($label_id);
      $operation = new AdGroupLabelOperation();
      $operation->setOperand($adGroupLabel);
      $operation->setOperator(Operator::ADD);
      $operations[] = $operation;
}
$result = $adGroupService->mutate($operations);

But I get the error

Unmarshalling Error: cvc-elt.4.3: Type 'ns1:AdGroupLabelOperation' is not validly derived from the type definition, 'AdGroupOperation', of element 'ns1:operations'. 

Sadly there are very few examples of this so hopefully I can find some insight in sharing my problem.

[John VV]

I finally found the answer.

The hint is in the docs: https://developers.google.com/adwords/api/docs/guides/labels

But bonus mutateLabels is not a valid function for adgroups so digging into the library code I found "mutateLabel" and voila.

$adGroupService->mutateLabel($operations);

Is what you'll need.