I don't think that any of the _del_XXX methods in GrampsInMemBD can work.
For example, the _del_person methods is defined like this:
There is no 'person' object in scope here. It is the same for all the other
I also found a minor typo in _do_remove_object in GrampsDbBase.py.
if not self.readonly:
handle = str(handle)
if not trans.batch:
old_data = dmap.get(handle)
I think that 'transaction.add' should be 'trans.add'.
I have fixed this in the SOUR_REPO branch for now.