private <T extends Expression> boolean containsExpression(Class<T> searchFor) {
        var searcher = new ExpressionSearcher<>(searchFor);
        var expr = searcher.searchIn(script);
        return (expr != null);
    }
This class wraps an indexing script expression, with some helper methods for extracting information from it.

@author arnej27959
config-model/src/main/java/com/yahoo/schema/parser/ParsedIndexingOp.java