Ocaml in Jupyter - Tab Completion

I am using ocaml with jupyter. Tab completion seems to work only with some packages and not others. For example List.<tab> , a pop-up window appears with all functions in this module. However, Core.<tab> does nothing.
I have installed merlin and ran opam user-setup install as instructed in the documentation. This should detected installed packages as well as standard built-in ocaml packages for tab completion
Am I doing something wrong or missing a step?

Solved my own question. I was missing a step.
In order for merlin to detect installed packages, a file with name .merlin must be created in the project root directory. Inside this file, list the packages. Here is an example:

PKG core