class_docstr: A hooks that restored variables from a given checkpoints.
  
  Params:
    prefix: Variables matching this prefix are restored.
    checkpoint_path: Path to the checkpoint to restore variables from.
code: def __init__(self, params, model_dir, run_config):
      super(VariableRestoreHook, self).__init__(
          params, model_dir, run_config
      )
      self._saver = None
  
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 1 to create a new VariableRestoreHook object from inherited base classes: TrainingHook with example: obj = VariableRestoreHook(params, model_dir, run_config)