error generating tensorflow model

When I run the data / download.py I have no problem but then when I run the code to make the model I get this error:

Traceback (most recent call last):
  File "\Python\deep_speech\deep_speech.py", line 404, in <module>
    app.run(main)
  File "\AppData\Local\Programs\Python\Python36\lib\site-packages\absl\app.py", line 300, in run
    _run_main(main, args)
  File "\AppData\Local\Programs\Python\Python36\lib\site-packages\absl\app.py", line 251, in _run_main
    sys.exit(main(argv))
  File "\Python\deep_speech\deep_speech.py", line 397, in main
    run_deep_speech(flags_obj)
  File "\Python\deep_speech\deep_speech.py", line 210, in run_deep_speech
    train_speech_dataset = generate_dataset(flags_obj.train_data_dir)
  File "\Python\deep_speech\deep_speech.py", line 199, in generate_dataset
    flags_obj.sortagrad
  File "\Python\deep_speech\data\dataset.py", line 71, in __init__
    assert tf.gfile.Exists(data_path)
AssertionError

The code I used is the one on the tensorflow page on github link