public static Set<HostGroup> fromHostGroupComponents(Map<String, Set<String>> hostGroupComponents) {
      return hostGroupComponents.entrySet().stream()
        .map(entry -> create(entry.getKey(), entry.getValue()))
        .collect(toSet());
    }
@return value attributes in <i>attribute name -> property name -> value</i> format
ambari-server/src/main/java/org/apache/ambari/server/api/services/stackadvisor/recommendations/RecommendationResponse.java