How to split project based on .pyproject file into sub modules?

[Borys]

I have Git Python PySide2 project with several Git Submodules. Each Submodule have .pyproject file. I did not find any tutorials, how to import .pyproject file to another .pyproject. Where can I get documentation about .pyproject files or is there another way to open Python project with Git Submodules in QtCreator without .pyproject?