code: private OperationPair createRemoveOperation(ProductPartitionNode node) {
      Preconditions.checkNotNull(node.getProductPartitionId(),
          "Node for REMOVE operation has no partition ID: %s", node);
      Preconditions.checkArgument(node.getProductPartitionId().longValue() >= 0L,
          "Node for REMOVE operation has a negative partition ID: %s", node);
  
      AdGroupCriterionOperation removeOp = new AdGroupCriterionOperation();
      removeOp.setOperator(Operator.REMOVE);
      removeOp.setOperand(ProductPartitionNodeAdapter.createCriterionForRemove(node, adGroupId));
  
      return new OperationPair(node, removeOp);
    }
docs: Returns a REMOVE operation for the specified node.