private NotItem removeNot(CompositeItem composite) {
        for (int i = 0; i < composite.getItemCount(); i++) {
            if (composite.getItem(i) instanceof NotItem) {
                return (NotItem) composite.removeItem(i);
            }
        }
        return null;
    }
Removes and returns the first <i>not</i> found in the composite, or returns null if there's none
container-search/src/main/java/com/yahoo/prelude/query/parser/SimpleParser.java