Fork lexibank/pylexibank to your github account and install the development environment:
$ pip install virtualenv # might require sudo/admin privileges
$ git clone https://github.com/<your-handle>/pylexibank.git
$ cd pylexibank
$ python -m virtualenv .venv
$ source .venv/bin/activate # Windows: .venv\Scripts\activate.bat
$ pip install -r requirements.txt # installs the cloned version with dev-tools in development mode