Jupyter Notebook Organization w/ Reusable Code

Question

I'm using:

• Python3.7
• VS Code + Jupyter Notebook Extension
• Both macOS & Windows, and I keep my files in a Dropbox folder

I want to organize my notebooks into directories so it's easier to navigate my various projects. I also want to organize my reusable python code to somewhere accessible where it's easy to update and add new functions.

This is the file structure I have in mind:

/research
  /modules
    < reusable .py files >
  /subject_one
    < books >
  /subject_two
    < books >

However, I can't seem to import any of my reusable .py files this way.

Is there some way to make this work, or some similar alternative? It seems to be a real PITA to make my own python module on my local machine, so I'm hoping there's a solution which involves relative imports.