I've been looking through the "Create custom procedure blocks" documentation (https://developers.google.com/blockly/guides/create-custom-blocks/procedures/creating-custom-procedure-blocks) and it seems as though there's quite a few bugs in the code and that the guide is potentially also out of date.
Is there an updated guide on creating custom procedures using the @blockly/block-shareable-procedures plugin, or a barebones simple example of custom define/call procedure blocks?