How to use the datasets.imdb.imdb.merge_roidbs function in datasets

def rpn_roidb(self):
    if int(self._year) == 2007 or self._image_set != 'test':
      gt_roidb = self.gt_roidb()
      rpn_roidb = self._load_rpn_roidb(gt_roidb)
      roidb = imdb.merge_roidbs(gt_roidb, rpn_roidb)
    else:
      roidb = self._load_rpn_roidb(None)

    return roidb

def rpn_roidb(self):
        if int(self._year) == 2007 or self._image_set != 'test':
            gt_roidb = self.gt_roidb()
            rpn_roidb = self._load_rpn_roidb(gt_roidb)
            roidb = imdb.merge_roidbs(gt_roidb, rpn_roidb)
        else:
            roidb = self._load_rpn_roidb(None)

        return roidb

def rpn_roidb(self):
        if int(self._year) == 2007 or self._image_set != 'test':
            gt_roidb = self.gt_roidb()
            rpn_roidb = self._load_rpn_roidb(gt_roidb)
            roidb = imdb.merge_roidbs(gt_roidb, rpn_roidb)
        else:
            roidb = self._load_rpn_roidb(None)

        return roidb

def rpn_roidb(self):
    if self._image_set != 'test':
      gt_roidb = self.gt_roidb()
      rpn_roidb = self._load_rpn_roidb(gt_roidb)
      roidb = imdb.merge_roidbs(gt_roidb, rpn_roidb)
    else:
      roidb = self._load_rpn_roidb(None)

    return roidb

This function loads/saves from/to a cache file to speed up future calls.
        """
        cache_file = os.path.join(self.cache_path,
                                  self.name + '_selective_search_roidb.pkl')

        if os.path.exists(cache_file):
            with open(cache_file, 'rb') as fid:
                roidb = cPickle.load(fid)
            print '{} ss roidb loaded from {}'.format(self.name, cache_file)
            return roidb

        if int(self._year) == 2007 or self._image_set != 'test':
            gt_roidb = self.gt_roidb()
            ss_roidb = self._load_selective_search_roidb(gt_roidb)
            roidb = imdb.merge_roidbs(gt_roidb, ss_roidb)
        else:
            roidb = self._load_selective_search_roidb(None)
        with open(cache_file, 'wb') as fid:
            cPickle.dump(roidb, fid, cPickle.HIGHEST_PROTOCOL)
        print 'wrote ss roidb to {}'.format(cache_file)

        return roidb

def rpn_roidb(self):
    if self._image_set != 'test':
      gt_roidb = self.gt_roidb()
      rpn_roidb = self._load_rpn_roidb(gt_roidb)
      roidb = imdb.merge_roidbs(gt_roidb, rpn_roidb)
    else:
      roidb = self._load_rpn_roidb(None)

    return roidb

This function loads/saves from/to a cache file to speed up future calls.
        """
        cache_file = os.path.join(self.cache_path,
                                  self.name + '_selective_search_roidb.pkl')

        if os.path.exists(cache_file):
            with open(cache_file, 'rb') as fid:
                roidb = pickle.load(fid)
            print('{} ss roidb loaded from {}'.format(self.name, cache_file))
            return roidb

        if int(self._year) == 2007 or self._image_set != 'test':
            gt_roidb = self.gt_roidb()
            ss_roidb = self._load_selective_search_roidb(gt_roidb)
            roidb = imdb.merge_roidbs(gt_roidb, ss_roidb)
        else:
            roidb = self._load_selective_search_roidb(None)
        with open(cache_file, 'wb') as fid:
            pickle.dump(roidb, fid, pickle.HIGHEST_PROTOCOL)
        print('wrote ss roidb to {}'.format(cache_file))

        return roidb

This function loads/saves from/to a cache file to speed up future calls.
        """
        cache_file = os.path.join(self.cache_path,
                                  self.name + '_selective_search_roidb.pkl')

        if os.path.exists(cache_file):
            with open(cache_file, 'rb') as fid:
                roidb = cPickle.load(fid)
            print '{} ss roidb loaded from {}'.format(self.name, cache_file)
            return roidb

        if int(self._year) == 2007 or self._image_set != 'test':
            gt_roidb = self.gt_roidb()
            ss_roidb = self._load_selective_search_roidb(gt_roidb)
            roidb = imdb.merge_roidbs(gt_roidb, ss_roidb)
        else:
            roidb = self._load_selective_search_roidb(None)
        with open(cache_file, 'wb') as fid:
            cPickle.dump(roidb, fid, cPickle.HIGHEST_PROTOCOL)
        print 'wrote ss roidb to {}'.format(cache_file)

        return roidb

This function loads/saves from/to a cache file to speed up future calls.
        """

        cache_file = os.path.join(self.cache_path,
                                  '%s_%s_roidb_ss.pkl' % (self.name, self._split))

        if os.path.exists(cache_file):
            with open(cache_file, 'rb') as fid:
                roidb = cPickle.load(fid)
            print '{} ss roidb loaded from {}'.format(self.name, cache_file)
            return roidb

        if self._image_set != 'test':
            gt_roidb = self.gt_roidb()
            ss_roidb = self._load_selective_search_roidb(gt_roidb)
            roidb = imdb.merge_roidbs(gt_roidb, ss_roidb)
        else:
            roidb = self.test_roidb(None)
        with open(cache_file, 'wb') as fid:
            cPickle.dump(roidb, fid)
        print 'wrote ss roidb to {}'.format(cache_file)

        return roidb