text: from helper.dataset.pascal_voc import PascalVOC
  from helper.processing.roidb import prepare_roidb, add_bbox_regression_targets
  
  
  def load_train_roidb(image_set, year, root_path, devkit_path, flip=False):
      voc = PascalVOC(image_set, year, root_path, devkit_path)
      gt_roidb = voc.gt_roidb()
      ss_roidb = voc.selective_search_roidb(gt_roidb)
      if flip:
          ss_roidb = voc.append_flipped_images(ss_roidb)
      prepare_roidb(voc, ss_roidb)
      means, stds = add_bbox_regression_targets(ss_roidb)
      return voc, ss_roidb, means, stds
  
  
  def load_test_roidb(image_set, year, root_path, devkit_path):
      voc = PascalVOC(image_set, year, root_path, devkit_path)
      gt_roidb = voc.gt_roidb()
      ss_roidb = voc.selective_search_roidb(gt_roidb)
      prepare_roidb(voc, ss_roidb)
      return voc, ss_roidb
  