code: def set_label(self, infohash_list, label):
          
          data = self._process_infohash_list(infohash_list)
          data['label'] = label
          return self._post('command/setLabel', data=data)
docs: Set the label on multiple torrents.
          IMPORTANT: OLD API method, kept as it is to avoid breaking stuffs.
  
          :param infohash_list: Single or list() of infohashes.