code: def testVocabularyIsAllTrain(self):
      problem = FakeDistributedProblem()
  
      tmp_dir = problem.tmp_dir
  
      for text in problem.generate_text_for_vocab(tmp_dir, tmp_dir):
          # All the vocabulary is coming from training input shards.
          self.assertTrue("train_" in text, "train is not in %s" % text)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import shutil
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.data_generators import text_problems
  import tensorflow.compat.v1
  from tensorflow.compat.v1 import estimator
label_desc: Use image node_id 5 for calling the DistributedText2TextProblemsTest obj's underlying member method code with example usage: obj.testVocabularyIsAllTrain() without return types