code: public PhotoList<Photo> getPopularPhotos(Date date, StatsSort sort, int perPage, int page) throws FlickrException {
  
          Map<String, Object> parameters = new HashMap<String, Object>();
          parameters.put("method", METHOD_GET_POPULAR_PHOTOS);
          if (date != null) {
              parameters.put("date", String.valueOf(date.getTime() / 1000L));
          }
          if (sort != null) {
              parameters.put("sort", sort.name());
          }
          addPaginationParameters(parameters, perPage, page);
  
          Response response = transportAPI.get(transportAPI.getPath(), parameters, apiKey, sharedSecret);
          if (response.isError()) {
              throw new FlickrException(response.getErrorCode(), response.getErrorMessage());
          }
  
          return parsePopularPhotos(response);
      }
docs: List the photos with the most views, comments or favorites.
  
  @param date
  (Optional) Stats will be returned for this date. A day according to Flickr Stats starts at midnight GMT for all users, and timestamps will
  automatically be rounded down to the start of the day. If no date is provided, all time view counts will be returned.
  @param sort
  (Optional) The order in which to sort returned photos. Defaults to views. The possible values are views, comments and favorites. Other sort
  options are available through flickr.photos.search.
  @param perPage
  (Optional) Number of referrers to return per page. If this argument is omitted, it defaults to 25. The maximum allowed value is 100.
  @param page
  (Optional) The page of results to return. If this argument is omitted, it defaults to 1.
  @throws FlickrException
  @see "http://www.flickr.com/services/api/flickr.stats.getPopularPhotos.html"