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