Past versions of Toyplot up-to 0.18 supported Python 2 and Python 3 with a single code base. However, you should be aware that Python 2 will no longer be maintained past 2020 (https://pythonclock.org), and Toyplot is one of many projects to pledge an end to support for Python 2 (https://python3statement.org). In particular, Toyplot no longer supports Python 2 as of December 31st, 2018.

What this means

The Toyplot 0.18 branch was the final release that included Python 2 support. Starting with Toyplot 0.19, portability code has been removed and our automated regression tests are only run using Python 3. Of course, developers are free to continue working with the 0.18 branch if they need to support Python 2, and we will consider pull requests for the 0.18 branch on a case-by-case basis.