It's becauase the argument passed to the chr() method is out of the range. Want to learn more Python for Data Science? Head over to DataCamp and try their free Python Tutorial
The second product used in this project is Liquitex pouring medium. This is a low viscosity (very fluid), clear, and high gloss acrylic medium. It is about the consistency of warm honey; quite sticky also. It can ben used with your regular heavy body paint to make them flow easier, and create cool dripping effects.
As you paint, keep a misting bottle of water nearby to help keep paint on your palette moist. If you find your paint is too thick, you can thin acrylic paint with either water or acrylic medium. Using a palette knife is usually the easiest way to mix acrylic paints.