private List<Pair<String, StorageTierProperties>> getEnabledTiers(
            TieredStorageProperties storageProperties) {
        Set<Map.Entry<String, StorageTierProperties>> tierEntries = storageProperties.getTiers()
                .entrySet();
        if (tierEntries.isEmpty()) {
            return Collections.emptyList();
        }
        int tierSize = tierEntries.size();
        List<Pair<String, StorageTierProperties>> tiers = new ArrayList<>(tierSize);
        int i = 0;
        for (Map.Entry<String, StorageTierProperties> nameAndProperties : tierEntries) {
            StorageTierProperties properties = nameAndProperties.getValue();
            int days = properties.getDays();
            if (days <= 0 && i != tierSize - 1) {
                throw new IllegalArgumentException(
                        "The days of non-latest tiered storage properties must be more than 0");
            }
            if (properties.isEnabled()) {
                tiers.add(Pair.of(nameAndProperties.getKey(), nameAndProperties.getValue()));
            }
            i++;
        }
        if (tiers.isEmpty()) {
            return Collections.emptyList();
        }
        return tiers;
    }
@return True if all collections have existed
turms-service/src/main/java/im/turms/service/storage/mongo/MongoCollectionInitializer.java