presto-parser/src/main/java/io/prestosql/sql/tree/IfExpression.java/IfExpression/getChildren
class IfExpression:    @Override
    public List<Node> getChildren()
    {
        ImmutableList.Builder<Node> nodes = ImmutableList.builder();
        falseValue.ifPresent(nodes::add);
        return nodes.add(condition)
                .add(trueValue)
                .build();
    }