Vega is a Python-based tool that lets you build interactive visualizations. You don't actually have to write any imperative code. Altair and Vega kind of like do the rest for you. It's really nice. One of the things that I think is a little ironic is for the people who create these tools, like the people who created Altair, they have to write so much JavaScript and not that much Python. Because they're building these interactive beautiful experiences on the front end for us, we get to write the Python.