code: def create_examples_train(candidate_dialog_paths, rng, positive_probability=0.5, max_context_length=20):
      
      i = 0
      examples = []
      for context_dialog in candidate_dialog_paths:
          if i % 1000 == 0:
              print str(i)
          dialog_path = candidate_dialog_paths[i]
          examples.append(create_single_dialog_train_example(dialog_path, candidate_dialog_paths, rng, positive_probability,
                                                             max_context_length=max_context_length))
          i += 1
docs: Creates single training example.
      :param candidate_dialog_paths:
      :param rng:
      :param positive_probability: probability of selecting positive training example
      :return: