class_docstr: MSCOCO, character level.
code: def generator(self, data_dir, tmp_dir, is_training):
      if is_training:
          return mscoco_generator(data_dir, tmp_dir, True, 80000)
      else:
          return mscoco_generator(data_dir, tmp_dir, False, 40000)
      raise NotImplementedError()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import io
  import json
  import os
  import random
  import zipfile
  from tensor2tensor.data_generators import generator_utils
  from tensor2tensor.data_generators import image_utils
  from tensor2tensor.data_generators import imagenet
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.data_generators import translate_ende
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
label_desc: Use image node_id 6 for calling the ImageMsCocoCharacters obj's underlying member method code with example usage: obj.generator(data_dir, tmp_dir, is_training) and returns: mscoco_generator, mscoco_generator