Vision ZM1701 Setting user codes

I can’t seem to set my Vision deadbolt’s user codes. Trying the lock.set_usercode developer function produces no errors, but I see nothing come up in the logs, and the code isn’t working. Does anyone have experience with this?

This one caught me out as well. The usercode value needs to be in quotes.
For example:

{"node_id:18,"code_slot":4,"usercode":"54321"}

The lock will beep after a successful code change