How to structure package for streamlit

All,
I am trying to figure out what is the best way to structure my package to be able to build streamlit apps within my package. I tried to follow different resources like (Structuring Your Project — The Hitchhiker's Guide to Python) while setting up the structure and it largely works fine until I attempted to start adding streamlit apps. The closest example that explains my issue is here (python - 'Attempted relative import in non-package' although packages with __init__.py in one directory - Stack Overflow)

Here is a high level overview of my package:

Package_Name
    docs
    examples
    toolbox 
       tool_1.py
       tool_2.py 
       tool_1_app.py
       utils.py 
       enumerations.py 
    tests 
       test_tool_1.py
       test_tool_2.py 
    configuration.py 
    environment.yml 
    README.md 

Until, I attempted tool_1_app.py which is the streamlit app, everything worked fine. But, when I launch tool_1_app.py I get a ModuleNotFoundError indicating that toolboxis not in the path. I can probably add the path using sys.append('../'), however, I would like to understand how I can avoid that by structuring my package better. Any help is appreciated.

Thanks
Uday