## oplog.mark_done()


Complete a started entry: what happened, and anything `undo` learnt


Usage

``` python
oplog.mark_done(
    root,
    op_id,
    result,
    pre=None,
    *,
    undone=None,
)
```


only while the operation ran (branch heads it replaced, for one). An undo names the entry it reversed in the same record, so completing the undo and marking its target undone is one append - there is no state where the undo is done but its target still counts as undoable.