Course 5 Week 2 Assignment 2

Wonder why sentences_to_indices unit test stop functioning, no error but also no result.
I reloaded also the same; but some time “submit Assignment” button also disappeared.
Pls advise.

When the submit button disappears, it usually means you need to restart the kernel.
Or you can try saving and re-loading the notebook.
Or you can try closing your browser and log into Coursera again.