Thonny is a nice option to create a PY file, open Python files, and edit PY files on Windows 10. This open-source tool has a simple interface and it is intended to use for beginners.

To make that work, create a “stub” file—a .py file in the top levet of your project that takes the same steps to run your application as the contents of the __main__.py file.

In complex projects that have too many functions, I prefer to have separate Python script files for my different functions and then import those into the streamlit_app.py or create a separate app ...

Simply create a new .py file in the same folder as your main Python code. Then “import” that file as you now know how to do, then access the functions from within that module.