Because you might want to get keyboard/mouse/gamepad/HID input into your CircuitPython projects without having to think much about USB.

1. Copy the adafruit_hid CircuitPython library bundle into the lib directory on your CircuitPython device.
2. Copy the ch559.py file into the lib directory on your CircuitPython device.
3. Hook up the CH559's Tx and Rx pins to your desired UART pins on the CircuitPython device. (In the example image below, I am using pins D6 (TX) and D7 (RX) on a Seeeduino XIAO). Also, make sure your CH995 is powered - this will depend on the breakout board you're using.
4. See code.py for usage. tl;dr:
   1. Create a UART instance.
   2. Create an instance of Ch559, passing the UART in as a dependency.
   3. repeatedly call ch559.poll() to get the latest events.

Example connection using a Seeeduino XIAO and a CH559 breakout from MatzElectronics on Tindie.