@Override
  public Map<String, Object> getUserPreferences(String principalName) {
    DynamoDB dynamoDB = new DynamoDB(documentstoreClient.getClient());
    Table table = dynamoDB.getTable(USER_PREFERENCES);

    Item item = table.getItem(PRINCIPAL_NAME_KEY, principalName);
    return item == null ? null : item.asMap();
  }
  @Override
  public Map<String, Object> findInstitutionPreferences() {
    DynamoDB dynamoDB = new DynamoDB(documentstoreClient.getClient());
    Table table = dynamoDB.getTable(INSTITUTION_PREFERENCES);

    Item item = table.getItem(INSTITUTION_ID_KEY, "1232413535");
    return item == null ? null : item.asMap();
  }