This is happening due to a [refactor](https://github.com/adafruit/Adafruit_CircuitPython_MCP230xx/pull/11) of the MCP230xx library. A few issues have been opened in the MCP230xx repo: https://github.com/adafruit/Adafruit_CircuitPython_MCP230xx/issues/12 https://github.com/adafruit/Adafruit_CircuitPython_MCP230xx/issues/15 but should be here. PR #39 should fix this.