private void deriveAttributeAsArrayType(ImmutableSDField field) {
        if (field.isImportedField()) {
            deriveImportedAttributes(field);
            return;
        }
        Attribute attribute = field.getAttributes().get(field.getName());
        if (attribute != null) {
            applyRanking(field, attribute);
            attributes.put(attribute.getName(), attribute.convertToArray());
        }
    }
Derives one attribute. TODO: Support non-default named attributes
config-model/src/main/java/com/yahoo/schema/derived/AttributeFields.java