There are many instructions out there on how to do this, but none quite worked for me. I'm currently on a Mac running OS X Mojave (10.14.4)
These instructions got me closest, but I still couldn't get the python part of the equation to work.
Here's what worked for me.
First, install unixodbc using Homebrew. I highly recommend using Homebrew here because it's a little more complicated to install on its own.
brew install unixodbc