@Override
  public Quota getQuota(QuotaResource quotaResource, QuotaName quotaName) {
    if (quotaName != QuotaName.STORAGE_IN_GB) {
      return null;
    }

    QuotaResourceType resourceType = quotaResource.getQuotaResourceType();
    if (resourceType != QuotaResourceType.ACCOUNT && resourceType != QuotaResourceType.CONTAINER) {
      throw new IllegalArgumentException("Unsupported quota resource type: " + resourceType);
    }
    String resourceId = quotaResource.getResourceId();
    if (storageQuota.containsKey(resourceId)) {
      long quotaValue = storageQuota.get(resourceId);
      return new Quota(quotaName, quotaValue, quotaResource);
    }
    return null;
  }
Constructor to create a {@link JSONStringStorageQuotaSource}.
@param config The {@link QuotaSource}.
@param accountService The {@link AccountService} to use.e
@throws IOException
ambry-quota/src/main/java/com/github/ambry/quota/storage/JSONStringStorageQuotaSource.java