Are there any helpful posts or requirements into how to use tensor2tensor with a custom vocabulary? It's for a translation problem.

For example, do we need to include and as the first two lines in the vocabulary file, and UNK at the end?

I'm following the example from https://github.com/tensorflow/tensor2tensor/blob/master/tensor2tensor/data_generators/translate_ende.py and it seems like generate_samples will create a vocabulary file from a temporary one already?

Thank you.