code: public Response editPhotos(String photosetId, String primaryPhotoId, List<String> photoIds) throws JinxException {
      JinxUtils.validateParams(photosetId, primaryPhotoId, photoIds);
      Map<String, String> params = new TreeMap<>();
      params.put("method", "flickr.photosets.editPhotos");
      params.put("photoset_id", photosetId);
      params.put("primary_photo_id", primaryPhotoId);
      StringBuilder builder = new StringBuilder();
      for (String id : photoIds) {
        builder.append(id).append(',');
      }
      builder.deleteCharAt(builder.length() - 1);
      params.put("photo_ids", builder.toString());
  
      return jinx.flickrPost(params, Response.class);
    }
docs: Modify the photos in a photoset. Use this method to add, remove and re-order photos.
  <br>
  This method requires authentication with 'write' permission.
  <br>
  This method has no specific response - It returns an empty success response if it completes without error.
  
  @param photosetId     id of the photoset to modify. The photoset must belong to the calling user. Required.
  @param primaryPhotoId id of the photo to use as the 'primary' photo for the set. This id must also be passed along in photo_ids list argument. Required.
  @param photoIds       list of photo ids to include in the set. They will appear in the set in the order sent. This list must contain the primary photo id. All photos must belong to the owner of the set. This list of photos replaces the existing list. Call addPhoto to append a photo to a set. Required.
  @return success response if it completes without error.
  @throws JinxException if required parameters are null, or if there are any errors.
  @see <a href="https://www.flickr.com/services/api/flickr.photosets.editPhotos.html">flickr.photosets.editPhotos</a>