ModuleNotFoundError: No module named '_ltree'

[Mycallback]

I'm getting the below error.

python3.6/site-packages/ltree/init.py", line 1, in from _ltree import Ltree # noqa ModuleNotFoundError: No module named '_ltree'

I think you just need to change the import statement to - from ._ltree import Ltree and the same with the following import statement.

[dvarrazzo]

I guess it's because python 3, on which I've never tested this thing.