(I know you're just getting this from above, but `h[dsID] = datastream_object_for(dsID)` is implied on accessing the datastream. I think above it is just used for "clarity" (not that it helped me trying to remember the code), but here I think we can just write e.g.:

```
  h[dsId].set_the_profile_xml_from_some_blob(p_xml)
```