public static function getLocations($locations_to_be_displayed = null) {
    $db = \Drupal::database();
    $branches_list = [
      'branch' => [],
      'camp' => [],
    ];
    $query = $db->select('node_field_data', 'n')
      ->fields('n', ['nid', 'title', 'type'])
      ->condition('type', ['branch', 'camp'], 'IN')
      ->condition('status', 1);
    $items = $query->execute()->fetchAll();
    foreach ($items as $item) {
      // By default we show all locations instead of showing empty popup.
      if (!empty($locations_to_be_displayed) && !in_array($item->nid, $locations_to_be_displayed)) {
        continue;
      }
      $branches_list[$item->type][$item->nid] = $item->title;
    }

    return $branches_list;
  }