Optional<Index> getSchemaIndex(String name) {
        if (indices.containsKey(name)) return Optional.of(indices.get(name));
        if (inherited.isPresent()) return requireInherited().getSchemaIndex(name);
        return Optional.empty();
    }
Returns the schema level index of this name, in this or any inherited schema, if any
config-model/src/main/java/com/yahoo/schema/Schema.java