private void convertVarArgsAnd(OperatorNode<ExpressionOperator> ast, int argIdx, AndItem outAnd, NotItem outNot) {
        Iterable<OperatorNode<ExpressionOperator>> args = ast.getArgument(argIdx);
        for (OperatorNode<ExpressionOperator> arg : args) {
            assertHasOperator(arg, ExpressionOperator.class);
            if (arg.getOperator() == ExpressionOperator.NOT) {
                OperatorNode<ExpressionOperator> exp = arg.getArgument(0);
                assertHasOperator(exp, ExpressionOperator.class);
                outNot.addNegativeItem(convertExpression(exp));
            } else {
                outAnd.addItem(convertExpression(arg));
            }
        }
    }
Build a "pure" not, without any positive terms.
container-search/src/main/java/com/yahoo/search/yql/YqlParser.java