code: def _read(self):
          
          _, data_img_name, label_img_name = self.f.readline().strip('\n').split("\t")
          data = {}
          label = {}
          data[self.data_name], label[self.label_name] = self._read_img(data_img_name, label_img_name)
          return list(data.items()), list(label.items())
docs: get two list, each list contains two elements: name and nd.array value