code: def __call__(self, data, is_train):
      yield from batcher(data, self.batch_size)
  
file_path: gluonts/src/gluonts/dataset/loader.py
imports: import logging
  from typing import Callable, Iterable, Optional
  import numpy
  from gluonts.dataset import DataBatch, Dataset
  from gluonts.itertools import Cyclic, IterableSlice, PseudoShuffled, batcher, rows_to_columns
  from gluonts.pydantic import BaseModel
  from gluonts.transform import AdhocTransform, Identity, SelectFields, Transformation, Valmap
label_desc: Use image node_id 1 for calling the Batch obj's underlying member method code with example usage: obj.__call__(data, is_train) without return types