

Don't reinvent the wheel! Most parts of the code you will add for the new 🤗 Transformers model already exist
  somewhere in 🤗 Transformers. Take some time to find similar, already existing models and tokenizers you can copy
  from. grep and rg are your
  friends. Note that it might very well happen that your model's tokenizer is based on one model implementation, and
  your model's modeling code on another one. E.g. FSMT's modeling code is based on BART, while FSMT's tokenizer code
  is based on XLM.
It's more of an engineering challenge than a scientific challenge. You should spend more time creating an
  efficient debugging environment rather than trying to understand all theoretical aspects of the model in the paper.
Ask for help, when you're stuck! Models are the core component of 🤗 Transformers so we at Hugging Face are more
  than happy to help you at every step to add your model. Don't hesitate to ask if you notice you are not making
  progress.