Fork the repository by clicking on the 'Fork' button on the
   repository's page. This creates a copy of the code under your GitHub user account.

Clone your transformers fork to your local disk, and add the base repository as a remote:

git clone https://github.com/[your Github handle]/transformers.git
cd transformers
git remote add upstream https://github.com/huggingface/transformers.git

Set up a development environment, for instance by running the following command: