TypeError: slice indices must be integers or None or have an __index__ method

[loretoparisi]

(.env) [loretoparisi@:mbploreto tutorial]$ python shakespeare.py 
Starting Shakespeare
Successfully downloaded shakespear.txt 99993 bytes.
Traceback (most recent call last):
  File "shakespeare.py", line 253, in <module>
    tf.app.run()
  File "/Users/loretoparisi/Documents/MyProjects/prettytensor/.env/lib/python3.6/site-packages/tensorflow/python/platform/app.py", line 48, in run
    _sys.exit(main(_sys.argv[:1] + flags_passthrough))
  File "shakespeare.py", line 211, in main
    shakespeare = data_utils.shakespeare(TIMESTEPS + 1)
  File "/Users/loretoparisi/Documents/MyProjects/prettytensor/.env/lib/python3.6/site-packages/prettytensor-0.7.2-py3.6.egg/prettytensor/tutorial/data_utils.py", line 135, in shakespeare
    0:len(shakespeare_full) / chunk_size * chunk_size]
TypeError: slice indices must be integers or None or have an __index__ method

Since the shakespeare.py did not work due to the issue #56 I have used the PR #57 doing

$ virtualenv -p python3 .env
$ pip install tensorflow
$ python setup.py build
$ python setup.py build
$ cd prettytensor/tutorial/
$ python shakespeare.py