class_docstr: Abstract base class for training hooks.
    
docstr: Returns the directory model checkpoints are written to.
      
docstr_tok: ["Returns","the","directory","model","checkpoints","are","written","to","."]
code: def model_dir(self):
      """Returns the directory model checkpoints are written to."""
      return os.path.abspath(self._model_dir)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import abc
  import os
  import numpy
  import six
  import yaml
  import tensorflow
  from tensorflow.python.training.basic_session_run_hooks import SecondOrStepTimer
  from tensorflow.python.training import session_manager
  from tensorflow.python.client import timeline
  from tensorflow import gfile
  from seq2seq.configurable import Configurable, abstractstaticmethod
  from seq2seq import graph_utils, global_vars
label_desc: Use image node_id 2 for calling the TrainingHook obj's underlying member method code with example usage: obj.model_dir() and returns: os