code: def _training_stats(self):
          
  
          fields = self._list_fields()
          stat_fields = ['training_time',
                         'training_iterations']
          if 'validation_perplexity' in fields:
              stat_fields.append('validation_perplexity')
  
          ret = {k : self._get(k) for k in stat_fields}
          return ret
docs: Return a dictionary of statistics collected during creation of the
          model. These statistics are also available with the ``get`` method and
          are described in more detail in that method's documentation.
  
          Returns
          -------
          out : dict
              Dictionary of statistics compiled during creation of the
              TopicModel.
  
          See Also
          --------
          summary
  
          Examples
          --------
          >>> docs = turicreate.SArray('https://static.turi.com/datasets/nips-text')
          >>> m = turicreate.topic_model.create(docs)
          >>> m._training_stats()
          {'training_iterations': 20,
           'training_time': 20.5034}