hello @burnier & everyone else with the same problem,
the latest version of Python is 3.7
DrawBot currently embeds Python 3.6
if you recently installed “Python 3” from python.org, you probably have 3.7.
to make modules available in DrawBot, they need to be installed for Python 3.6 (not 3.7).
so, the first step is to make sure that you have Python 3.6 installed in your system. you can check that by typing python3.6 in Terminal. if you get -bash: python3.6: command not found, then you need to install Python 3.6 first. you can get it from python.org/downloads.
pip is included in Python, so once you have Python 3.6 you should have pip3.6 too. please give it a try, and let us know how it goes… good luck!