Hello lgs777,
In the version 1.1.0 there were some major changes in Python API, so please check updated API Reference document.
In your code you need to replace doc.activeChunk by doc.chunk at first. And then change function arguments from string to enum:
doc.chunk.matchPhotos(accuracy = PhotoScan.HighAccuracy, preselection = PhotoScan.Preselection.GenericPreselection)
Note that you can always use autocomplete feature (Ctrl + Space) to see the description of the function in the Console pane.