class MetricsResponse {

    private Map<MetricsType, MetricsResponseSingleValue> results;

    private MetricsResponseSingleValue singleResult;

    public MetricsResponseSingleValue getSingleResult() {<FILL_FUNCTION_BODY>}
}

        if (singleResult == null) {
            this.singleResult = results.entrySet()
                    .stream()
                    .findFirst()
                    .map(Map.Entry::getValue)
                    .orElse(MetricsResponseSingleValue.empty());
        }
        return singleResult;
    
<no_super_class>