> However I don't see the need to set the attribute if it doesn't exist?

If there is no `xml:id` attribute of the list which has the `text:continue:list' attribute, `applyContinuedNumberingById` will have problems to create proper rules, no? At least from what I understood the value of the `currentId` parameter needs to be set, otherwise 
```appendRule(styleSheet, setListId(newRule, currentId));```
will create something broken, no?

If `text:continue-list` references a not-existing list, that is another problem. Then indeed we don't have to do anything (though we might want to emit a warning with runtime.log).