Hi William,
The differences in summary what you notices, the use of preprocess models.
If you can avoid using all the Python code to do the BERT preprocessing you should! that will make your life much easier. Both when training the model and when serving where you’ll need to have the preprocessing code also available.
Why there’s a colab with the Python raw code then?
Because it will show you everything that is happening inside the preprocess model if you want to have a deeper understand. The other reason is, if you don’t have a preprocess model available, you will know what to do.