class_docstr: A collection of options that are passed to the training script
  and can be saved to perform inference later.
  
  Args:
    task: Name of the training task class.
    task_params: A dictionary of parameters passed to the training task.
docstr: Returns the path to the options file.
  
  Args:
    model_dir: The model directory
docstr_tok: ["Returns","the","path","to","the","options","file",".","Args",":","model_dir",":","The","model","directory"]
code: def path(model_dir):
      """Returns the path to the options file.
  
      Args:
        model_dir: The model directory
      """
      return os.path.join(model_dir, "train_options.json")
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import inspect
  import os
  from collections import defaultdict
  from pydoc import locate
  import json
  import tensorflow
  from tensorflow import gfile
  from seq2seq.contrib import rnn_cell
label_desc: Use image node_id 4 for calling the TrainOptions obj's underlying member method code with example usage: obj.path(model_dir) and returns: os