kujyp issues

Results 3 issues of


                                            kujyp

![screenshot_20180212-152956](https://user-images.githubusercontent.com/19223089/36085535-a83fa376-1009-11e8-8312-8ba6d1f58faa.png)

help wanted

#315

- Fix broken m4t_prepare_dataset guides cause from https://github.com/facebookresearch/seamless_communication/pull/443

CLA Signed