code: public Photos getClusterPhotos(String tag, List<String> clusterId) throws JinxException {
      JinxUtils.validateParams(tag, clusterId);
      StringBuilder sb = new StringBuilder();
      for (String s : clusterId) {
        sb.append(s).append("-");
      }
      if (sb.length() > 0) {
        sb.deleteCharAt(sb.length() - 1);
      }
      return getClusterPhotos(tag, sb.toString());
    }
docs: Returns the first 24 photos for a given tag cluster
  
  This method does not require authentication.
  
  This method will combine the Strings in the clusterId list.
  
  @param tag       the tag that the cluster belongs to. Required.
  @param clusterId top three tags for the cluster. Required.
  @return first 24 photos for a given tag cluster.
  @throws JinxException if required parameters are missing, or if there are any errors.
  @see <a href="https://www.flickr.com/services/api/flickr.tags.getClusterPhotos.html">flickr.tags.getClusterPhotos</a>