This release corrects a link to the learn guide tutorial that is in the documentation pages. Thank you adam-huganir.
To use in CircuitPython, simply install the [Adafruit CircuitPython Bundle](https://circuitpython.org/libraries).
To use in CPython, `pip3 install adafruit-circuitpython-TCA8418`.
Read the [docs](http://circuitpython.readthedocs.io/projects/TCA8418/en/latest/) for info on how to use it.