Contribution guidelines

All contributions to TLViz are welcome! If you find a bug or an error in the documentation, we very much appreciate an issue or a pull request!

How to contribute

If you find a bug, or have an idea for a new feature, and you want to know if the contribution is relevant and not being worked on, you can open a new issue. For major bugs, it can also be useful to include a minimal, reproducible example, to make it as easy as possible to fix it.

You can submit implementation of new features or bug/documentation fixes as a pull-request.

Development environment

We recommend using a virtual environment to develop TLViz locally on your machine. For example, with Anaconda

conda create -n tlviz python=3.8 anaconda

Then, you can download the TLViz source code and install it together with all the development dependencies

git clone
cd viz
pip install -e .[devel,test,docs]

This will install TLViz in editable mode, so any change to the source code will be applied to the installed version too.

Style guide

TLViz follows the Black style (with a maximum line length of 120 characters) and follows most of the flake8 guidelines (except E203, W503). Most style errors will be fixed automatically in VSCode if you include the following lines in your settings.json file

    "python.linting.flake8Enabled": true,
    "python.formatting.provider": "black",
    "editor.formatOnSave": false,
    "python.linting.flake8Args": [
    "python.sortImports.args": [
    "[python]": {
        "editor.codeActionsOnSave": {
            "source.organizeImports": true

Unit tests

TLViz aims to have a high test coverage, so any new code should also include tests, including visualisation. You can run the tests by running


To also check the test coverage

coverage html

This will generate a HTML report where you can see all lines not covered by any tests.


The documentation is generated using sphinx with automatic API documentation from the docstrings and MathJax for equations. We use sphinx-gallery to generate the example gallery. To expand this, simply add a new example script with a name matching the pattern plot_*.py in the examples-directory (make sure to follow the sphinx-gallery style for your scripts).

To ensure that the documentation is up to date, we use doctest, which will evaluate all examples and compare with the expected output. Examples should therefore be seeded.