Trying to write a CircuitPython module for 4/8 port relay modules

I’ve been working on porting the Arduino example control code for the I2C relay modules and I’ve hit the wall.
As far as I can tell the module loads fine, and the test script runs and outputs expected behavior, however the relays never toggle.
I’m running this on a RockPi 4b+ and have verified the functioning of the I2C port using other read only sensors. I’ve also verified the board is working using an Arduino and the example code.
My code repository is at https://github.com/PedanticAvenger/CircuitPython-GroveI2CRelay and I’d love if anyone can offer a pointer on something I might be missing.

Item of note,
i2cset -y 7 0x11 0x10 0x0F will turn on all relays and
i2cset -y 7 0x11 0x10 0x00 will turn them all off again