docs: public String addComment(String photosetId, String commentText) throws FlickrException {
          Map<String, Object> parameters = new HashMap<String, Object>();
          parameters.put("method", METHOD_ADD_COMMENT);
  
          parameters.put("photoset_id", photosetId);
          parameters.put("comment_text", commentText);
  
          // Note: This method requires an HTTP POST request.
          Response response = transportAPI.post(transportAPI.getPath(), parameters, apiKey, sharedSecret);
          if (response.isError()) {
              throw new FlickrException(response.getErrorCode(), response.getErrorMessage());
          }
          // response:
          // <comment id="97777-12492-72057594037942601" />
          Element commentElement = response.getPayload();
          return commentElement.getAttribute("id");
      }